diff --git a/src/event/EventMixin.js b/src/event/EventMixin.js
index 4d1d8f52..86163df6 100644
--- a/src/event/EventMixin.js
+++ b/src/event/EventMixin.js
@@ -119,14 +119,19 @@ var EventMixin = {
 
         var eventListeners = listeners[eventType];
         if(eventListeners){
-            eventListeners = eventListeners.slice(0);
+            var eventListenersCopy = eventListeners.slice(0);
             event = event || new EventObject(eventType, this, detail);
             if(event._stopped) return false;
 
-            for(var i = 0; i < eventListeners.length; i++){
-                var el = eventListeners[i];
+            for(var i = 0; i < eventListenersCopy.length; i++){
+                var el = eventListenersCopy[i];
                 el.listener.call(this, event);
-                if(el.once) eventListeners.splice(i--, 1);
+                if(el.once) {
+                    var index = eventListeners.indexOf(el);
+                    if(index > -1){
+                        eventListeners.splice(index, 1);
+                    }
+                }
             }
 
             if(eventListeners.length == 0) delete listeners[eventType];
diff --git a/test/event.js b/test/event.js
index be888edc..c9406379 100644
--- a/test/event.js
+++ b/test/event.js
@@ -20,6 +20,7 @@ describe('event', function(){
 
         it('on once', function(){
             var firedNum = 0;
+            eventTarget.on('hello', function(e){});
             eventTarget.on('hello', function(e){
                 firedNum ++;
             }, true);