diff --git a/pkg/controllers/gameserver/gameserver_manager_test.go b/pkg/controllers/gameserver/gameserver_manager_test.go
index 7424039d..76ec2dcb 100644
--- a/pkg/controllers/gameserver/gameserver_manager_test.go
+++ b/pkg/controllers/gameserver/gameserver_manager_test.go
@@ -1,14 +1,32 @@
 package gameserver
 
 import (
+	kruiseV1alpha1 "github.com/openkruise/kruise-api/apps/v1alpha1"
+	kruiseV1beta1 "github.com/openkruise/kruise-api/apps/v1beta1"
 	gameKruiseV1alpha1 "github.com/openkruise/kruise-game/apis/v1alpha1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/intstr"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
 	"reflect"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/client/fake"
 	"testing"
 )
 
+var (
+	scheme = runtime.NewScheme()
+)
+
+func init() {
+	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
+	utilruntime.Must(gameKruiseV1alpha1.AddToScheme(scheme))
+	utilruntime.Must(kruiseV1beta1.AddToScheme(scheme))
+	utilruntime.Must(kruiseV1alpha1.AddToScheme(scheme))
+}
+
 func TestSyncServiceQualities(t *testing.T) {
 	up := intstr.FromInt(20)
 	dp := intstr.FromInt(10)
@@ -279,3 +297,201 @@ func TestSyncServiceQualities(t *testing.T) {
 		}
 	}
 }
+
+func TestSyncGsToPod(t *testing.T) {
+	up := intstr.FromInt(20)
+	dp := intstr.FromInt(10)
+	tests := []struct {
+		gs       *gameKruiseV1alpha1.GameServer
+		pod      *corev1.Pod
+		isUpdate bool
+	}{
+		{
+			gs: &gameKruiseV1alpha1.GameServer{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "xxx-0",
+					Labels: map[string]string{
+						gameKruiseV1alpha1.GameServerOwnerGssKey: "xxx",
+					},
+				},
+				Spec: gameKruiseV1alpha1.GameServerSpec{
+					UpdatePriority:   &up,
+					DeletionPriority: &dp,
+					OpsState:         gameKruiseV1alpha1.WaitToDelete,
+				},
+			},
+			pod: &corev1.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "xxx-0",
+				},
+				Status: corev1.PodStatus{
+					Phase: corev1.PodPending,
+				},
+			},
+			isUpdate: true,
+		},
+
+		{
+			gs: &gameKruiseV1alpha1.GameServer{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "xxx-0",
+					Labels: map[string]string{
+						gameKruiseV1alpha1.GameServerOwnerGssKey: "xxx",
+					},
+				},
+				Spec: gameKruiseV1alpha1.GameServerSpec{
+					UpdatePriority:   &up,
+					DeletionPriority: &dp,
+					OpsState:         gameKruiseV1alpha1.WaitToDelete,
+				},
+				Status: gameKruiseV1alpha1.GameServerStatus{
+					CurrentState: gameKruiseV1alpha1.Creating,
+				},
+			},
+			pod: &corev1.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "xxx-0",
+					Labels: map[string]string{
+						gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.WaitToDelete),
+						gameKruiseV1alpha1.GameServerDeletePriorityKey: dp.String(),
+						gameKruiseV1alpha1.GameServerUpdatePriorityKey: up.String(),
+						gameKruiseV1alpha1.GameServerStateKey:          string(gameKruiseV1alpha1.Creating),
+					},
+				},
+				Status: corev1.PodStatus{
+					Phase: corev1.PodPending,
+				},
+			},
+			isUpdate: false,
+		},
+	}
+
+	for _, test := range tests {
+		objs := []client.Object{test.gs, test.pod}
+		c := fake.NewClientBuilder().WithScheme(scheme).WithObjects(objs...).Build()
+		manager := &GameServerManager{
+			client:     c,
+			gameServer: test.gs,
+			pod:        test.pod,
+		}
+
+		isUpdate, err := manager.SyncGsToPod()
+		if err != nil {
+			t.Error(err)
+		}
+
+		if isUpdate != test.isUpdate {
+			t.Errorf("expect isUpdate is %v ,but actually is %v", test.isUpdate, isUpdate)
+		}
+	}
+}
+
+func TestSyncNetworkStatus(t *testing.T) {
+	fakeTime := metav1.Now()
+	portInternal := intstr.FromInt(80)
+	portExternal := intstr.FromInt(601)
+	tests := []struct {
+		gs              *gameKruiseV1alpha1.GameServer
+		pod             *corev1.Pod
+		gsNetworkStatus gameKruiseV1alpha1.NetworkStatus
+	}{
+		{
+			gs: &gameKruiseV1alpha1.GameServer{
+				Status: gameKruiseV1alpha1.GameServerStatus{
+					NetworkStatus: gameKruiseV1alpha1.NetworkStatus{},
+				},
+			},
+			pod: &corev1.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Annotations: map[string]string{
+						gameKruiseV1alpha1.GameServerNetworkType:     "xxx-type",
+						gameKruiseV1alpha1.GameServerNetworkConf:     "[{\"name\":\"SlbIds\",\"value\":\"lb-2zev1w12n684h7ymjtpuo\"},{\"name\":\"PortProtocols\",\"value\":\"80\"},{\"name\":\"Fixed\",\"value\":\"true\"}]",
+						gameKruiseV1alpha1.GameServerNetworkDisabled: "false",
+						gameKruiseV1alpha1.GameServerNetworkStatus:   "{\"internalAddresses\":[{\"ip\":\"172.16.1.132\",\"ports\":[{\"name\":\"80\",\"protocol\":\"TCP\",\"port\":80}],\"portRange\":{}}],\"externalAddresses\":[{\"ip\":\"47.99.47.99\",\"ports\":[{\"name\":\"80\",\"protocol\":\"TCP\",\"port\":601}],\"portRange\":{}}],\"currentNetworkState\":\"Ready\",\"createTime\":null,\"lastTransitionTime\":null}",
+					},
+				},
+			},
+			gsNetworkStatus: gameKruiseV1alpha1.NetworkStatus{
+				NetworkType:         "xxx-type",
+				DesiredNetworkState: gameKruiseV1alpha1.NetworkReady,
+				CreateTime:          fakeTime,
+				LastTransitionTime:  fakeTime,
+			},
+		},
+
+		{
+			gs: &gameKruiseV1alpha1.GameServer{
+				Status: gameKruiseV1alpha1.GameServerStatus{
+					NetworkStatus: gameKruiseV1alpha1.NetworkStatus{
+						NetworkType:         "xxx-type",
+						DesiredNetworkState: gameKruiseV1alpha1.NetworkReady,
+						CreateTime:          fakeTime,
+						LastTransitionTime:  fakeTime,
+					},
+				},
+			},
+			pod: &corev1.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Annotations: map[string]string{
+						gameKruiseV1alpha1.GameServerNetworkType:     "xxx-type",
+						gameKruiseV1alpha1.GameServerNetworkConf:     "[{\"name\":\"SlbIds\",\"value\":\"lb-2zev1w12n684h7ymjtpuo\"},{\"name\":\"PortProtocols\",\"value\":\"80\"},{\"name\":\"Fixed\",\"value\":\"true\"}]",
+						gameKruiseV1alpha1.GameServerNetworkDisabled: "false",
+						gameKruiseV1alpha1.GameServerNetworkStatus:   "{\"internalAddresses\":[{\"ip\":\"172.16.1.132\",\"ports\":[{\"name\":\"80\",\"protocol\":\"TCP\",\"port\":80}],\"portRange\":{}}],\"externalAddresses\":[{\"ip\":\"47.99.47.99\",\"ports\":[{\"name\":\"80\",\"protocol\":\"TCP\",\"port\":601}],\"portRange\":{}}],\"currentNetworkState\":\"Ready\",\"createTime\":null,\"lastTransitionTime\":null}",
+					},
+				},
+			},
+			gsNetworkStatus: gameKruiseV1alpha1.NetworkStatus{
+				NetworkType:         "xxx-type",
+				CurrentNetworkState: gameKruiseV1alpha1.NetworkReady,
+				DesiredNetworkState: gameKruiseV1alpha1.NetworkReady,
+				InternalAddresses: []gameKruiseV1alpha1.NetworkAddress{
+					{
+						IP: "172.16.1.132",
+						Ports: []gameKruiseV1alpha1.NetworkPort{
+							{
+								Name:     "80",
+								Protocol: "TCP",
+								Port:     &portInternal,
+							},
+						},
+					},
+				},
+				ExternalAddresses: []gameKruiseV1alpha1.NetworkAddress{
+					{
+						IP: "47.99.47.99",
+						Ports: []gameKruiseV1alpha1.NetworkPort{
+							{
+								Name:     "80",
+								Protocol: "TCP",
+								Port:     &portExternal,
+							},
+						},
+					},
+				},
+				CreateTime:         fakeTime,
+				LastTransitionTime: fakeTime,
+			},
+		},
+	}
+
+	for _, test := range tests {
+		objs := []client.Object{test.gs, test.pod}
+		c := fake.NewClientBuilder().WithScheme(scheme).WithObjects(objs...).Build()
+		manager := &GameServerManager{
+			client:     c,
+			gameServer: test.gs,
+			pod:        test.pod,
+		}
+
+		actual := manager.syncNetworkStatus()
+		actual.CreateTime = fakeTime
+		actual.LastTransitionTime = fakeTime
+		if !reflect.DeepEqual(test.gsNetworkStatus, actual) {
+			t.Errorf("expect gsNetworkStatus is %v ,but actually is %v", test.gsNetworkStatus, actual)
+		}
+	}
+}
diff --git a/pkg/controllers/gameserverset/gameserverset_manager_test.go b/pkg/controllers/gameserverset/gameserverset_manager_test.go
new file mode 100644
index 00000000..6d8ac43a
--- /dev/null
+++ b/pkg/controllers/gameserverset/gameserverset_manager_test.go
@@ -0,0 +1,567 @@
+package gameserverset
+
+import (
+	"context"
+	kruiseV1alpha1 "github.com/openkruise/kruise-api/apps/v1alpha1"
+	kruiseV1beta1 "github.com/openkruise/kruise-api/apps/v1beta1"
+	gameKruiseV1alpha1 "github.com/openkruise/kruise-game/apis/v1alpha1"
+	"github.com/openkruise/kruise-game/pkg/util"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/utils/pointer"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/client/fake"
+	"testing"
+)
+
+var (
+	scheme = runtime.NewScheme()
+)
+
+func init() {
+	utilruntime.Must(gameKruiseV1alpha1.AddToScheme(scheme))
+	utilruntime.Must(kruiseV1beta1.AddToScheme(scheme))
+	utilruntime.Must(kruiseV1alpha1.AddToScheme(scheme))
+}
+
+func TestComputeToScaleGs(t *testing.T) {
+	tests := []struct {
+		newGssReserveIds []int
+		oldGssreserveIds []int
+		notExistIds      []int
+		expectedReplicas int
+		pods             []corev1.Pod
+		newNotExistIds   []int
+	}{
+		{
+			newGssReserveIds: []int{2, 3, 4},
+			oldGssreserveIds: []int{2, 3},
+			notExistIds:      []int{5},
+			expectedReplicas: 3,
+			pods: []corev1.Pod{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "xxx-0",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "10",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "xxx-1",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.Maintaining),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "xxx-4",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.WaitToDelete),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "xxx-6",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+			},
+			newNotExistIds: []int{5},
+		},
+	}
+
+	for _, test := range tests {
+		newNotExistIds := computeToScaleGs(test.newGssReserveIds, test.oldGssreserveIds, test.notExistIds, test.expectedReplicas, test.pods)
+		if !util.IsSliceEqual(newNotExistIds, test.newNotExistIds) {
+			t.Errorf("expect newNotExistIds %v but got %v", test.newNotExistIds, newNotExistIds)
+		}
+	}
+}
+
+func TestIsNeedToScale(t *testing.T) {
+	tests := []struct {
+		gss    *gameKruiseV1alpha1.GameServerSet
+		asts   *kruiseV1beta1.StatefulSet
+		result bool
+	}{
+		{
+			gss: &gameKruiseV1alpha1.GameServerSet{
+				Spec: gameKruiseV1alpha1.GameServerSetSpec{
+					Replicas: pointer.Int32(5),
+				},
+			},
+			asts: &kruiseV1beta1.StatefulSet{
+				Spec: kruiseV1beta1.StatefulSetSpec{
+					Replicas: pointer.Int32(5),
+				},
+				Status: kruiseV1beta1.StatefulSetStatus{
+					Replicas: int32(5),
+				},
+			},
+			result: false,
+		},
+		{
+			gss: &gameKruiseV1alpha1.GameServerSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Annotations: map[string]string{gameKruiseV1alpha1.GameServerSetReserveIdsKey: "1,5"},
+				},
+				Spec: gameKruiseV1alpha1.GameServerSetSpec{
+					Replicas:             pointer.Int32(5),
+					ReserveGameServerIds: []int{1, 5},
+				},
+			},
+			asts: &kruiseV1beta1.StatefulSet{
+				Spec: kruiseV1beta1.StatefulSetSpec{
+					Replicas: pointer.Int32(5),
+				},
+				Status: kruiseV1beta1.StatefulSetStatus{
+					Replicas: int32(5),
+				},
+			},
+			result: false,
+		},
+	}
+	for _, test := range tests {
+		manager := &GameServerSetManager{
+			gameServerSet: test.gss,
+			asts:          test.asts,
+		}
+		actual := manager.IsNeedToScale()
+		if actual != test.result {
+			t.Errorf("expect spec %v but got %v", test.result, actual)
+		}
+	}
+}
+
+func TestGameServerScale(t *testing.T) {
+	recorder := record.NewFakeRecorder(100)
+
+	tests := []struct {
+		gss            *gameKruiseV1alpha1.GameServerSet
+		asts           *kruiseV1beta1.StatefulSet
+		podList        []corev1.Pod
+		astsReserveIds []int
+		gssReserveIds  string
+	}{
+		// case0: scale down without reserveIds
+		{
+			gss: &gameKruiseV1alpha1.GameServerSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace:   "xxx",
+					Name:        "case0",
+					Annotations: map[string]string{gameKruiseV1alpha1.GameServerSetReserveIdsKey: "1"},
+				},
+				Spec: gameKruiseV1alpha1.GameServerSetSpec{
+					Replicas:             pointer.Int32(3),
+					ReserveGameServerIds: []int{1},
+				},
+			},
+			asts: &kruiseV1beta1.StatefulSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "case0",
+				},
+				Spec: kruiseV1beta1.StatefulSetSpec{
+					Replicas:        pointer.Int32(4),
+					ReserveOrdinals: []int{1},
+				},
+				Status: kruiseV1beta1.StatefulSetStatus{
+					Replicas: int32(4),
+				},
+			},
+			podList: []corev1.Pod{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case0-0",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "10",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case0-2",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.WaitToDelete),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case0-3",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case0-4",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.Maintaining),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+			},
+			astsReserveIds: []int{1, 2},
+			gssReserveIds:  "1",
+		},
+		// case1: scale down with reserveIds
+		{
+			gss: &gameKruiseV1alpha1.GameServerSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace:   "xxx",
+					Name:        "case1",
+					Annotations: map[string]string{gameKruiseV1alpha1.GameServerSetReserveIdsKey: "1"},
+				},
+				Spec: gameKruiseV1alpha1.GameServerSetSpec{
+					Replicas:             pointer.Int32(3),
+					ReserveGameServerIds: []int{1, 0},
+				},
+			},
+			asts: &kruiseV1beta1.StatefulSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "case1",
+				},
+				Spec: kruiseV1beta1.StatefulSetSpec{
+					Replicas:        pointer.Int32(4),
+					ReserveOrdinals: []int{1},
+				},
+				Status: kruiseV1beta1.StatefulSetStatus{
+					Replicas: int32(4),
+				},
+			},
+			podList: []corev1.Pod{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case1-0",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "10",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case1-2",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.WaitToDelete),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case1-3",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case1-4",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.Maintaining),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+			},
+			astsReserveIds: []int{1, 0},
+			gssReserveIds:  "1,0",
+		},
+		// case2: scale up with reserveIds
+		{
+			gss: &gameKruiseV1alpha1.GameServerSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace:   "xxx",
+					Name:        "case2",
+					Annotations: map[string]string{gameKruiseV1alpha1.GameServerSetReserveIdsKey: "1"},
+				},
+				Spec: gameKruiseV1alpha1.GameServerSetSpec{
+					Replicas:             pointer.Int32(5),
+					ReserveGameServerIds: []int{},
+				},
+			},
+			asts: &kruiseV1beta1.StatefulSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "case2",
+				},
+				Spec: kruiseV1beta1.StatefulSetSpec{
+					Replicas:        pointer.Int32(4),
+					ReserveOrdinals: []int{1},
+				},
+				Status: kruiseV1beta1.StatefulSetStatus{
+					Replicas: int32(4),
+				},
+			},
+			podList: []corev1.Pod{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case2-0",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "10",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case2-2",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.WaitToDelete),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case2-3",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case2-4",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.Maintaining),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+			},
+			astsReserveIds: nil,
+			gssReserveIds:  "",
+		},
+		// case3: scale up with both reserveIds and others
+		{
+			gss: &gameKruiseV1alpha1.GameServerSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace:   "xxx",
+					Name:        "case3",
+					Annotations: map[string]string{gameKruiseV1alpha1.GameServerSetReserveIdsKey: "1"},
+				},
+				Spec: gameKruiseV1alpha1.GameServerSetSpec{
+					Replicas:             pointer.Int32(5),
+					ReserveGameServerIds: []int{},
+				},
+			},
+			asts: &kruiseV1beta1.StatefulSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "case3",
+				},
+				Spec: kruiseV1beta1.StatefulSetSpec{
+					Replicas:        pointer.Int32(3),
+					ReserveOrdinals: []int{1, 3},
+				},
+				Status: kruiseV1beta1.StatefulSetStatus{
+					Replicas: int32(3),
+				},
+			},
+			podList: []corev1.Pod{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case3-0",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.None),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "10",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case3-2",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.WaitToDelete),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "case3-4",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOpsStateKey:       string(gameKruiseV1alpha1.Maintaining),
+							gameKruiseV1alpha1.GameServerDeletePriorityKey: "0",
+						},
+					},
+				},
+			},
+			astsReserveIds: nil,
+			gssReserveIds:  "",
+		},
+	}
+
+	for _, test := range tests {
+		objs := []client.Object{test.asts, test.gss}
+		c := fake.NewClientBuilder().WithScheme(scheme).WithObjects(objs...).Build()
+		manager := &GameServerSetManager{
+			gameServerSet: test.gss,
+			asts:          test.asts,
+			podList:       test.podList,
+			eventRecorder: recorder,
+			client:        c,
+		}
+
+		if err := manager.GameServerScale(); err != nil {
+			t.Error(err)
+		}
+
+		updateAsts := &kruiseV1beta1.StatefulSet{}
+		if err := manager.client.Get(context.TODO(), types.NamespacedName{
+			Namespace: test.asts.Namespace,
+			Name:      test.asts.Name,
+		}, updateAsts); err != nil {
+			t.Error(err)
+		}
+		if !util.IsSliceEqual(updateAsts.Spec.ReserveOrdinals, test.astsReserveIds) {
+			t.Errorf("expect asts ReserveOrdinals %v but got %v", test.astsReserveIds, updateAsts.Spec.ReserveOrdinals)
+		}
+
+		updateGss := &gameKruiseV1alpha1.GameServerSet{}
+		if err := manager.client.Get(context.TODO(), types.NamespacedName{
+			Namespace: test.gss.Namespace,
+			Name:      test.gss.Name,
+		}, updateGss); err != nil {
+			t.Error(err)
+		}
+		if updateGss.GetAnnotations()[gameKruiseV1alpha1.GameServerSetReserveIdsKey] != test.gssReserveIds {
+			t.Errorf("expect asts ReserveOrdinals %v but got %v", test.gssReserveIds, updateGss.GetAnnotations()[gameKruiseV1alpha1.GameServerSetReserveIdsKey])
+		}
+	}
+}
+
+func TestSyncGameServerReplicas(t *testing.T) {
+	tests := []struct {
+		gss      *gameKruiseV1alpha1.GameServerSet
+		podList  []corev1.Pod
+		gsList   []*gameKruiseV1alpha1.GameServer
+		toDelete []int
+	}{
+		{
+			gss: &gameKruiseV1alpha1.GameServerSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Namespace: "xxx",
+					Name:      "xxx",
+				},
+			},
+			podList: []corev1.Pod{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "xxx-0",
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "xxx-2",
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name: "xxx-4",
+					},
+				},
+			},
+			gsList: []*gameKruiseV1alpha1.GameServer{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: "xxx",
+						Name:      "xxx-0",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOwnerGssKey: "xxx",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: "xxx",
+						Name:      "xxx-2",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOwnerGssKey: "xxx",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: "xxx",
+						Name:      "xxx-3",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOwnerGssKey: "xxx",
+						},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: "xxx",
+						Name:      "xxx-4",
+						Labels: map[string]string{
+							gameKruiseV1alpha1.GameServerOwnerGssKey: "xxx",
+						},
+					},
+				},
+			},
+			toDelete: []int{3},
+		},
+	}
+
+	for _, test := range tests {
+		objs := []client.Object{test.gss}
+		for _, gs := range test.gsList {
+			objs = append(objs, gs)
+		}
+		c := fake.NewClientBuilder().WithScheme(scheme).WithObjects(objs...).Build()
+		recorder := record.NewFakeRecorder(100)
+		manager := &GameServerSetManager{
+			gameServerSet: test.gss,
+			podList:       test.podList,
+			eventRecorder: recorder,
+			client:        c,
+		}
+		if err := manager.SyncGameServerReplicas(); err != nil {
+			t.Error(err)
+		}
+
+		gsList := &gameKruiseV1alpha1.GameServerList{}
+		if err := manager.client.List(context.Background(), gsList, &client.ListOptions{
+			Namespace: test.gss.GetNamespace(),
+			LabelSelector: labels.SelectorFromSet(map[string]string{
+				gameKruiseV1alpha1.GameServerOwnerGssKey: test.gss.GetName(),
+				gameKruiseV1alpha1.GameServerDeletingKey: "true",
+			})}); err != nil {
+			t.Error(err)
+		}
+
+		actual := util.GetIndexListFromGsList(gsList.Items)
+		expect := test.toDelete
+		if !util.IsSliceEqual(actual, expect) {
+			t.Errorf("expect to delete gameservers %v but actually %v", expect, actual)
+		}
+	}
+}