diff --git a/ios/sdk/module/animation2/pop/HPOPAnimator.mm b/ios/sdk/module/animation2/pop/HPOPAnimator.mm
index 21a3df3a650..21981085074 100644
--- a/ios/sdk/module/animation2/pop/HPOPAnimator.mm
+++ b/ios/sdk/module/animation2/pop/HPOPAnimator.mm
@@ -532,11 +532,14 @@ - (void)_scheduleProcessPendingList
   pthread_mutex_unlock(&_lock);
 }
 
-- (void)_renderTime:(CFTimeInterval)time items:(std::list<POPAnimatorItemRef>)items
+- (void)_renderTime:(CFTimeInterval)time items:(std::list<POPAnimatorItemRef> &)items
 {
   // begin transaction with actions disabled
   [CATransaction begin];
   [CATransaction setDisableActions:YES];
+    
+  // lock
+  pthread_mutex_lock(&_lock);
 
   // notify delegate
   NSArray *allDelegates = _animatorDelegates.allObjects;
@@ -544,9 +547,6 @@ - (void)_renderTime:(CFTimeInterval)time items:(std::list<POPAnimatorItemRef>)it
     [delegate animatorWillAnimate:self];
   }
 
-  // lock
-  pthread_mutex_lock(&_lock);
-
   // count active animations
   const NSUInteger count = items.size();
   if (0 == count) {