diff --git a/src/core/6.inject.js b/src/core/6.inject.js
index 0f9b04fc6..25c324602 100644
--- a/src/core/6.inject.js
+++ b/src/core/6.inject.js
@@ -11,10 +11,9 @@
         if (moduleInjection[xtype] != null) {
             _global.console && console.error("module： [" + xtype + "] 已经注册过了");
         }
-        var key;
         for (var k in moduleInjectionMap) {
             if(cls[k]){
-                for (key in cls[k]) {
+                for (var key in cls[k]) {
                     if (!moduleInjectionMap[k][key]) {
                         moduleInjectionMap[k][key] = [];
                     }