diff --git a/.eslintrc.js b/.eslintrc.js
index 3ef7a83..cc76f52 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -38,6 +38,8 @@ module.exports = {
     'prettier/prettier': ['error', { endOfLine: 'auto' }],
 
     'no-plusplus': 'off',
+    'no-fallthrough': 'off',
+
     '@typescript-eslint/explicit-function-return-type': 'off',
     '@typescript-eslint/strict-boolean-expressions': 'off',
     '@typescript-eslint/no-non-null-assertion': 'off',
diff --git a/src/composables/useToday.ts b/src/composables/useToday.ts
index df49008..8db1771 100644
--- a/src/composables/useToday.ts
+++ b/src/composables/useToday.ts
@@ -10,11 +10,11 @@ export default () => {
   const { $styleBox } = useStyle();
 
   const today = new XDate();
-  today.startOf();
+  today.startOf(ganttHeader.unit);
 
   const todayLeft = computed(() => {
     const start = ganttHeader.start?.clone();
-    start?.startOf();
+    start?.startOf(ganttHeader.unit);
     return (
       (today.intervalTo(start) / currentMillisecond.value) *
       ganttColumnWidth.value
diff --git a/src/models/param/date.ts b/src/models/param/date.ts
index 4d32503..87ae473 100644
--- a/src/models/param/date.ts
+++ b/src/models/param/date.ts
@@ -129,12 +129,25 @@ export class XDate {
   }
 
   /**
-   * 将日期置为当日最开始（0点0分0秒）
+   * 件日期置为单位的起始位置
    */
-  startOf() {
-    this.date.setHours(0);
-    this.date.setMinutes(0);
-    this.date.setSeconds(0);
-    this.date.setMilliseconds(0);
+  startOf(unit: DateUnit) {
+    switch (unit) {
+      case 'year':
+        this.date.setMonth(0);
+      case 'month':
+        this.date.setDate(1);
+      case 'week':
+        this.date.setDate(this.date.getDate() - day(this.date).day());
+      case 'day':
+        this.date.setHours(0);
+      case 'hour':
+        this.date.setMinutes(0);
+      case 'minute':
+        this.date.setSeconds(0);
+      case 'second':
+        this.date.setMilliseconds(0);
+        break;
+    }
   }
 }
diff --git a/src/models/param/header.ts b/src/models/param/header.ts
index 0a42a05..827908e 100644
--- a/src/models/param/header.ts
+++ b/src/models/param/header.ts
@@ -215,6 +215,7 @@ class GanttHeader extends Header {
   ) {
     this.unit = unit;
     this.start = start?.getOffset(-Variables.time.millisecondOf[this.unit]);
+    this.start?.startOf(this.unit);
     this.end = end;
     this.minLength = minLen;