diff --git a/apisix/schema_def.lua b/apisix/schema_def.lua
index f7b117af93da..280680729d50 100644
--- a/apisix/schema_def.lua
+++ b/apisix/schema_def.lua
@@ -508,7 +508,7 @@ local upstream_schema = {
 _M.upstream_hash_vars_schema = {
     type = "string",
     pattern = [[^((uri|server_name|server_addr|request_uri|remote_port]]
-               .. [[|remote_addr|query_string|host|hostname)]]
+               .. [[|remote_addr|query_string|host|hostname|mqtt_client_id)]]
                .. [[|arg_[0-9a-zA-z_-]+)$]],
 }
 
diff --git a/t/admin/upstream3.t b/t/admin/upstream3.t
index e40e24e99b4a..335bbfae36db 100644
--- a/t/admin/upstream3.t
+++ b/t/admin/upstream3.t
@@ -442,7 +442,7 @@ passed
     }
 --- error_code: 400
 --- response_body
-{"error_msg":"invalid configuration: failed to match pattern \"^((uri|server_name|server_addr|request_uri|remote_port|remote_addr|query_string|host|hostname)|arg_[0-9a-zA-z_-]+)$\" with \"not_support\""}
+{"error_msg":"invalid configuration: failed to match pattern \"^((uri|server_name|server_addr|request_uri|remote_port|remote_addr|query_string|host|hostname|mqtt_client_id)|arg_[0-9a-zA-z_-]+)$\" with \"not_support\""}
 
 
 
@@ -521,7 +521,7 @@ passed
     }
 --- error_code: 400
 --- response_body
-{"error_msg":"invalid configuration: failed to match pattern \"^((uri|server_name|server_addr|request_uri|remote_port|remote_addr|query_string|host|hostname)|arg_[0-9a-zA-z_-]+)$\" with \"not_support\""}
+{"error_msg":"invalid configuration: failed to match pattern \"^((uri|server_name|server_addr|request_uri|remote_port|remote_addr|query_string|host|hostname|mqtt_client_id)|arg_[0-9a-zA-z_-]+)$\" with \"not_support\""}
 
 
 
diff --git a/t/stream-plugin/mqtt-proxy2.t b/t/stream-plugin/mqtt-proxy2.t
index 8c797a353d77..35211878e330 100644
--- a/t/stream-plugin/mqtt-proxy2.t
+++ b/t/stream-plugin/mqtt-proxy2.t
@@ -75,3 +75,110 @@ passed
 --- error_log
 failed to parse domain: loc, error:
 --- timeout: 10
+
+
+
+=== TEST 3: set upstream(id: 1)
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/upstreams/1',
+                ngx.HTTP_PUT,
+                [[{
+                    "type": "chash",
+                    "key": "mqtt_client_id",
+                    "nodes": [
+                    {
+                        "host": "0.0.0.0",
+                        "port": 1995,
+                        "weight": 1
+                    },
+                    {
+                        "host": "127.0.0.1",
+                        "port": 1995,
+                        "weight": 1
+                    }
+                    ]
+                }]]
+            )
+
+            ngx.status = code
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+
+
+
+=== TEST 4: balance with mqtt_client_id
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/stream_routes/1',
+                ngx.HTTP_PUT,
+                [[{
+                    "remote_addr": "127.0.0.1",
+                    "server_port": 1985,
+                    "plugins": {
+                        "mqtt-proxy": {
+                            "protocol_name": "MQTT",
+                            "protocol_level": 5
+                        }
+                    },
+                    "upstream_id": 1
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+
+
+
+=== TEST 5: hit route with empty id
+--- stream_request eval
+"\x10\x0d\x00\x04\x4d\x51\x54\x54\x05\x02\x00\x3c\x00\x00\x00"
+--- stream_response
+hello world
+--- grep_error_log eval
+qr/(mqtt client id: \w+|proxy request to \S+)/
+--- grep_error_log_out
+proxy request to 127.0.0.1:1995
+
+
+
+=== TEST 6: hit route with different client id, part 1
+--- stream_request eval
+"\x10\x0e\x00\x04\x4d\x51\x54\x54\x05\x02\x00\x3c\x00\x00\x01\x66"
+--- stream_response
+hello world
+--- grep_error_log eval
+qr/(mqtt client id: \w+|proxy request to \S+)/
+--- grep_error_log_out
+mqtt client id: f
+proxy request to 0.0.0.0:1995
+
+
+
+=== TEST 7: hit route with different client id, part 2
+--- stream_request eval
+"\x10\x0e\x00\x04\x4d\x51\x54\x54\x05\x02\x00\x3c\x00\x00\x01\x67"
+--- stream_response
+hello world
+--- grep_error_log eval
+qr/(mqtt client id: \w+|proxy request to \S+)/
+--- grep_error_log_out
+mqtt client id: g
+proxy request to 127.0.0.1:1995