diff --git a/src/core/base.js b/src/core/base.js
index e073da354..20a57bd30 100644
--- a/src/core/base.js
+++ b/src/core/base.js
@@ -3,7 +3,7 @@
  * Create By GUY 2014\11\17
  *
  */
-var _global;
+_global = undefined;
 if (typeof window !== "undefined") {
     _global = window;
 } else if (typeof global !== "undefined") {
diff --git a/src/core/foundation.js b/src/core/foundation.js
index e8555e32e..067178cbd 100644
--- a/src/core/foundation.js
+++ b/src/core/foundation.js
@@ -4,7 +4,7 @@
 /**
  * 初始化BI对象
  */
-var _global;
+_global = undefined;
 if (typeof window !== "undefined") {
     _global = window;
 } else if (typeof global !== "undefined") {