diff --git a/yudao-module-im/yudao-module-im-api/src/main/java/cn/iocoder/yudao/module/im/enums/message/ImMessageTypeEnum.java b/yudao-module-im/yudao-module-im-api/src/main/java/cn/iocoder/yudao/module/im/enums/message/ImMessageTypeEnum.java
index 59b435d..c778a31 100644
--- a/yudao-module-im/yudao-module-im-api/src/main/java/cn/iocoder/yudao/module/im/enums/message/ImMessageTypeEnum.java
+++ b/yudao-module-im/yudao-module-im-api/src/main/java/cn/iocoder/yudao/module/im/enums/message/ImMessageTypeEnum.java
@@ -26,10 +26,14 @@ public enum ImMessageTypeEnum implements ArrayValuable<Integer> {
     RECEIPT(12, "回执"), // 暂无
     TIP_TEXT(21, "提示文本"), // 对应 TextMessage 类
 
-    RECALL(10, "撤回"),
-    READ(11, "已读"),
-    RECEIPT(12, "回执"),
-    TIP_TEXT(21, "提示文本");
+    // ==================== 非单聊、群聊存储的类型，100 开始 ====================
+
+    FRIEND_ADD(100, "好友添加"), // 暂无
+    FRIEND_DELETE(101, "好友删除"), // 暂无
+    FRIEND_UPDATE(102, "好友更新"), // 对应 FriendUpdateMessage 类
+
+    GROUP_CREATE(200, "群创建"), // 暂无
+    GROUP_UPDATE(201, "群信息变更"); // 暂无
 
     public static final Integer[] ARRAYS = Arrays.stream(values()).map(ImMessageTypeEnum::getType).toArray(Integer[]::new);
 
diff --git a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/dal/redis/message/GroupMessageReadRedisDAO.java b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/dal/redis/message/GroupMessageReadRedisDAO.java
index 3bc2159..4ef7dc3 100644
--- a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/dal/redis/message/GroupMessageReadRedisDAO.java
+++ b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/dal/redis/message/GroupMessageReadRedisDAO.java
@@ -61,6 +61,27 @@ public class GroupMessageReadRedisDAO {
         return result;
     }
 
+    /**
+     * 删除用户在某群的已读位置
+     *
+     * @param groupId 群编号
+     * @param userId  用户编号
+     */
+    public void deleteReadMaxMessageId(Long groupId, Long userId) {
+        String key = formatKey(groupId);
+        stringRedisTemplate.opsForHash().delete(key, userId.toString());
+    }
+
+    /**
+     * 删除某群所有用户的已读位置（整个 Hash Key）
+     *
+     * @param groupId 群编号
+     */
+    public void deleteReadMaxMessageIdMap(Long groupId) {
+        String key = formatKey(groupId);
+        stringRedisTemplate.delete(key);
+    }
+
     private static String formatKey(Long groupId) {
         return String.format(GROUP_MESSAGE_READ, groupId);
     }
diff --git a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/group/ImGroupMemberServiceImpl.java b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/group/ImGroupMemberServiceImpl.java
index f38e546..33cc814 100644
--- a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/group/ImGroupMemberServiceImpl.java
+++ b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/group/ImGroupMemberServiceImpl.java
@@ -73,7 +73,6 @@ public class ImGroupMemberServiceImpl implements ImGroupMemberService {
         return imGroupMemberMapper.selectById(id);
     }
 
-
     @Override
     public List<ImGroupMemberDO> getGroupMemberListByGroupId(Long groupId) {
         return imGroupMemberMapper.selectListByGroupId(groupId);
diff --git a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/group/ImGroupServiceImpl.java b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/group/ImGroupServiceImpl.java
index 359907d..e64a68a 100644
--- a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/group/ImGroupServiceImpl.java
+++ b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/group/ImGroupServiceImpl.java
@@ -12,6 +12,7 @@ import cn.iocoder.yudao.module.im.controller.admin.group.vo.ImGroupUpdateReqVO;
 import cn.iocoder.yudao.module.im.dal.dataobject.group.ImGroupDO;
 import cn.iocoder.yudao.module.im.dal.dataobject.group.ImGroupMemberDO;
 import cn.iocoder.yudao.module.im.dal.mysql.group.ImGroupMapper;
+import cn.iocoder.yudao.module.im.service.message.ImGroupMessageService;
 import cn.iocoder.yudao.module.im.service.websocket.ImWebSocketService;
 import cn.iocoder.yudao.module.im.service.websocket.dto.ImGroupMessageDTO;
 import jakarta.annotation.Resource;
@@ -33,7 +34,6 @@ import static cn.iocoder.yudao.module.im.dal.redis.RedisKeyConstants.GROUP;
 import static cn.iocoder.yudao.module.im.enums.ErrorCodeConstants.*;
 
 // TODO @芋艿：群主的调整，暂时不考虑。后续在弄；
-// DONE @AI：groupdo 增加一个缓存；spring cache 实现；
 /**
  * 群 Service 实现类
  *
@@ -50,6 +50,9 @@ public class ImGroupServiceImpl implements ImGroupService {
     @Lazy // 避免循环依赖
     private ImGroupMemberService groupMemberService;
     @Resource
+    @Lazy // 避免循环依赖
+    private ImGroupMessageService groupMessageService;
+    @Resource
     private ImWebSocketService webSocketService;
 
     @Override
@@ -125,7 +128,8 @@ public class ImGroupServiceImpl implements ImGroupService {
         updateObj.setDissolvedTime(LocalDateTime.now());
         groupMapper.updateById(updateObj);
 
-        // TODO @AI：清理已读缓存；
+        // 4. 清理已读缓存
+        groupMessageService.deleteReadMaxMessageIdMap(id);
         // TODO @AI：推送群解散的提示；
         // TODO @AI：推送群信息变化；
     }
diff --git a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/message/ImGroupMessageService.java b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/message/ImGroupMessageService.java
index 4cac3e8..0b6e53f 100644
--- a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/message/ImGroupMessageService.java
+++ b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/message/ImGroupMessageService.java
@@ -69,4 +69,24 @@ public interface ImGroupMessageService {
      */
     List<ImGroupMessageDO> getGroupMessageList(Long userId, ImGroupMessageListReqVO reqVO);
 
+    /**
+     * 清理用户在某群的已读位置缓存
+     * <p>
+     * 用于成员退群场景
+     *
+     * @param groupId 群编号
+     * @param userId  用户编号
+     */
+    void deleteReadMaxMessageId(Long groupId, Long userId);
+
+    /**
+     * 清理某群所有用户的已读位置缓存
+     * <p>
+     * 用于群解散场景
+     *
+     * @param groupId 群编号
+     */
+    void deleteReadMaxMessageIdMap(Long groupId);
+
 }
+
diff --git a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/message/ImGroupMessageServiceImpl.java b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/message/ImGroupMessageServiceImpl.java
index 6efc128..43b3998 100644
--- a/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/message/ImGroupMessageServiceImpl.java
+++ b/yudao-module-im/yudao-module-im-biz/src/main/java/cn/iocoder/yudao/module/im/service/message/ImGroupMessageServiceImpl.java
@@ -471,9 +471,18 @@ public class ImGroupMessageServiceImpl implements ImGroupMessageService {
                 member -> isMessageVisible(msg, member, member.getUserId()));
     }
 
+    @Override
+    public void deleteReadMaxMessageId(Long groupId, Long userId) {
+        groupMessageReadRedisDAO.deleteReadMaxMessageId(groupId, userId);
+    }
+
+    @Override
+    public void deleteReadMaxMessageIdMap(Long groupId) {
+        groupMessageReadRedisDAO.deleteReadMaxMessageIdMap(groupId);
+    }
 
     private ImGroupMessageServiceImpl getSelf() {
         return SpringUtil.getBean(getClass());
     }
 
-}
+}
\ No newline at end of file