diff --git a/inside-notices/src/main/java/cn/axzo/msg/center/message/service/card/domain/CardSendModel.java b/inside-notices/src/main/java/cn/axzo/msg/center/message/service/card/domain/CardSendModel.java
index d6029761..aeaff8b0 100644
--- a/inside-notices/src/main/java/cn/axzo/msg/center/message/service/card/domain/CardSendModel.java
+++ b/inside-notices/src/main/java/cn/axzo/msg/center/message/service/card/domain/CardSendModel.java
@@ -13,6 +13,7 @@ import lombok.Setter;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 
@@ -26,7 +27,7 @@ public class CardSendModel {
 
     private final CardRequestContext<CardSendRequest> requestContext;
     private final CardTemplate cardTemplate;
-    private final List<Card> cards = new ArrayList<>();
+    private final List<Card> cards = Collections.synchronizedList(new ArrayList<>());
 
     private GeneralMessagePushVO cardContent;
 
diff --git a/inside-notices/src/main/java/cn/axzo/msg/center/utils/RecordCursor.java b/inside-notices/src/main/java/cn/axzo/msg/center/utils/RecordCursor.java
index 9edfc409..0500d613 100644
--- a/inside-notices/src/main/java/cn/axzo/msg/center/utils/RecordCursor.java
+++ b/inside-notices/src/main/java/cn/axzo/msg/center/utils/RecordCursor.java
@@ -36,6 +36,7 @@ public class RecordCursor<T> implements Iterable<List<T>> {
         return new Iterator<List<T>>() {
 
             long maxId = 0;
+            // single thread producer
             volatile List<T> batch;
             Boolean batchConsumed;