diff --git a/package.json b/package.json
index 5095307..b789345 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "es.shim",
-  "version": "2.2.0",
+  "version": "2.2.1",
   "description": "实现部分新API, 以及一些常用的扩展方法",
   "keyworks": [
     "es5",
diff --git a/src/lib/date.js b/src/lib/date.js
index 07f7077..572785a 100644
--- a/src/lib/date.js
+++ b/src/lib/date.js
@@ -48,7 +48,7 @@ if (!Date.prototype.format) {
         week: this.getWeek(),
         month: this.getMonth() + 1,
         date: this.getDate(),
-        day: this.getDay() + 1,
+        day: this.getDay(),
         hours: this.getHours(),
         minutes: this.getMinutes(),
         seconds: this.getSeconds()