diff --git a/src/main/java/com/ai/da/service/impl/MessageCenterServiceImpl.java b/src/main/java/com/ai/da/service/impl/MessageCenterServiceImpl.java
index 19927bdb..6189548c 100644
--- a/src/main/java/com/ai/da/service/impl/MessageCenterServiceImpl.java
+++ b/src/main/java/com/ai/da/service/impl/MessageCenterServiceImpl.java
@@ -253,12 +253,14 @@ public class MessageCenterServiceImpl extends ServiceImpl<NotificationMapper, No
         // 计算总的系统通知数量
         QueryWrapper<Notification> queryWrapper = new QueryWrapper<>();
         queryWrapper.lambda().eq(Notification::getType, "system")
-                .gt(Notification::getCreateTime, account.getCreateDate())
                 .and(wrapper -> wrapper
                         .isNull(Notification::getReceiverId)
                         .or()
                         .eq(Notification::getReceiverId, receiverId)
                 );
+        if (Objects.nonNull(account)) {
+            queryWrapper.lambda().gt(Notification::getCreateTime, account.getCreateDate());
+        }
         Long totalSysCount = baseMapper.selectCount(queryWrapper);
 
         // 计算单个用户读了多少条系统数据