diff --git a/mpush-core/src/main/java/com/mpush/core/push/BroadcastPushTask.java b/mpush-core/src/main/java/com/mpush/core/push/BroadcastPushTask.java
index 3d38a5b5..39e80cee 100644
--- a/mpush-core/src/main/java/com/mpush/core/push/BroadcastPushTask.java
+++ b/mpush-core/src/main/java/com/mpush/core/push/BroadcastPushTask.java
@@ -19,6 +19,7 @@
 
 package com.mpush.core.push;
 
+import com.google.common.collect.Sets;
 import com.mpush.api.message.Message;
 import com.mpush.api.common.Condition;
 import com.mpush.api.connection.Connection;
@@ -51,7 +52,7 @@ public final class BroadcastPushTask implements PushTask {
 
     private final TimeLine timeLine = new TimeLine();
 
-    private final Set<String> successUserIds = new HashSet<>(1024);
+    private final Set<String> successUserIds = Sets.newConcurrentHashSet();
 
     private final FlowControl flowControl;