diff --git a/backend/archive-service/src/main/java/com/artedu/archive/service/ArchivePullService.java b/backend/archive-service/src/main/java/com/artedu/archive/service/ArchivePullService.java
index e843820..1f29bfc 100644
--- a/backend/archive-service/src/main/java/com/artedu/archive/service/ArchivePullService.java
+++ b/backend/archive-service/src/main/java/com/artedu/archive/service/ArchivePullService.java
@@ -292,7 +292,15 @@ public class ArchivePullService {
         
         Object tolistObj = msgMap.get("tolist");
         if (tolistObj instanceof java.util.List) {
-            message.setToUser(JsonUtils.toJson(tolistObj));
+            java.util.List<?> tolist = (java.util.List<?>) tolistObj;
+            if (tolist.size() > 1) {
+                // 群聊/多接收者：接收者 JSON 数组会超出 to_user(VARCHAR128) 触发 Data too long 截断，
+                // 导致整条群消息 INSERT 失败丢失。接收者列表已由下方 tolist(TEXT) 完整保存，
+                // 且读取侧(Controller/SessionService)查询会回退匹配 tolist，故此处 to_user 置空。
+                message.setToUser(null);
+            } else {
+                message.setToUser(JsonUtils.toJson(tolistObj));
+            }
         } else {
             message.setToUser((String) tolistObj);
         }