diff --git a/components/modal/index.jsx b/components/modal/index.jsx
index 8f2a294f63..e61711586d 100644
--- a/components/modal/index.jsx
+++ b/components/modal/index.jsx
@@ -63,9 +63,7 @@ export default React.createClass({
       // 100ms 内发生过点击事件，则从点击位置动画展示
       // 否则直接 zoom 展示
       // 这样可以兼容非点击方式展开
-      setTimeout(function() {
-        mousePosition = null;
-      }, 100);
+      setTimeout(() => mousePosition = null, 100);
     });
     mousePositionEventBinded = true;
   },