diff --git a/Realtime/Realtime/Internal/Connection/LCConnection.cs b/Realtime/Realtime/Internal/Connection/LCConnection.cs
index e724b26..25845f2 100644
--- a/Realtime/Realtime/Internal/Connection/LCConnection.cs
+++ b/Realtime/Realtime/Internal/Connection/LCConnection.cs
@@ -168,6 +168,7 @@ namespace LeanCloud.Realtime.Internal.Connection {
                     // 应答
                     int requestIndex = command.I;
                     if (requestToResponses.TryGetValue(command, out TaskCompletionSource<GenericCommand> tcs)) {
+                        requestToResponses.Remove(command);
                         if (command.HasErrorMessage) {
                             // 错误
                             ErrorCommand error = command.ErrorMessage;
@@ -179,7 +180,6 @@ namespace LeanCloud.Realtime.Internal.Connection {
                         } else {
                             tcs.TrySetResult(command);
                         }
-                        requestToResponses.Remove(command);
                     } else {
                         LCLogger.Error($"No request for {requestIndex}");
                     }
diff --git a/Realtime/Realtime/Internal/Controller/LCIMMessageController.cs b/Realtime/Realtime/Internal/Controller/LCIMMessageController.cs
index f9a3f2a..be64e0e 100644
--- a/Realtime/Realtime/Internal/Controller/LCIMMessageController.cs
+++ b/Realtime/Realtime/Internal/Controller/LCIMMessageController.cs
@@ -186,10 +186,13 @@ namespace LeanCloud.Realtime.Internal.Controller {
             LCIMMessage msg) {
             ReadCommand read = new ReadCommand();
             ReadTuple tuple = new ReadTuple {
-                Cid = convId,
-                Mid = msg.Id,
-                Timestamp = msg.SentTimestamp
+                Cid = convId
             };
+            // 当不传 msg 时，服务端将其收到的最后一条消息标记为已读，可能与客户端不一致
+            if (msg != null) {
+                tuple.Mid = msg.Id;
+                tuple.Timestamp = msg.SentTimestamp;
+            }
             read.Convs.Add(tuple);
             GenericCommand command = NewCommand(CommandType.Read);
             command.ReadMessage = read;
diff --git a/Realtime/Realtime/Public/Conversation/LCIMConversation.cs b/Realtime/Realtime/Public/Conversation/LCIMConversation.cs
index 77cb321..cff93b0 100644
--- a/Realtime/Realtime/Public/Conversation/LCIMConversation.cs
+++ b/Realtime/Realtime/Public/Conversation/LCIMConversation.cs
@@ -185,7 +185,7 @@ namespace LeanCloud.Realtime {
         /// </summary>
         /// <returns></returns>
         public virtual async Task Read() {
-            if (LastMessage == null) {
+            if (Unread == 0) {
                 return;
             }
             await Client.MessageController.Read(Id, LastMessage);
diff --git a/Realtime/Realtime/Public/LCIMClient.cs b/Realtime/Realtime/Public/LCIMClient.cs
index 0d33627..c7bb338 100644
--- a/Realtime/Realtime/Public/LCIMClient.cs
+++ b/Realtime/Realtime/Public/LCIMClient.cs
@@ -384,21 +384,12 @@ namespace LeanCloud.Realtime {
             if (string.IsNullOrEmpty(id)) {
                 throw new ArgumentNullException(nameof(id));
             }
-            if (LCIMConversation.IsTemporayConversation(id)) {
-                List<LCIMTemporaryConversation> temporaryConversationList = await ConversationController.GetTemporaryConversations(new string[] { id });
-                if (temporaryConversationList == null || temporaryConversationList.Count < 1) {
-                    return null;
-                }
-                return temporaryConversationList[0];
-            }
-            LCIMConversationQuery query = GetQuery()
-                .WhereEqualTo("objectId", id)
-                .Limit(1);
-            ReadOnlyCollection<LCIMConversation> results = await ConversationController.Find(query);
-            if (results == null || results.Count < 1) {
+
+            ReadOnlyCollection<LCIMConversation> convs = await GetConversationList(new string[] { id });
+            if (convs == null || convs.Count() == 0) {
                 return null;
             }
-            return results[0];
+            return convs.First();
         }
 
         /// <summary>
@@ -410,26 +401,12 @@ namespace LeanCloud.Realtime {
             if (ids == null || ids.Count() == 0) {
                 throw new ArgumentNullException(nameof(ids));
             }
-            // 区分临时对话
-            IEnumerable<string> tempConvIds = ids.Where(item => {
-                return LCIMConversation.IsTemporayConversation(item);
-            });
-            IEnumerable<string> convIds = ids.Where(item => {
-                return !tempConvIds.Contains(item);
-            });
-            List<LCIMConversation> conversationList = new List<LCIMConversation>();
-            if (tempConvIds.Count() > 0) {
-                List<LCIMTemporaryConversation> temporaryConversations = await ConversationController.GetTemporaryConversations(tempConvIds);
-                conversationList.AddRange(temporaryConversations);
+
+            IEnumerable<LCIMConversation> convs = await GetOrQueryConversations(ids);
+            if (convs == null) {
+                return default;
             }
-            if (convIds.Count() > 0) {
-                LCIMConversationQuery query = GetQuery()
-                    .WhereContainedIn("objectId", convIds)
-                    .Limit(convIds.Count());
-                ReadOnlyCollection<LCIMConversation> conversations = await ConversationController.Find(query);
-                conversationList.AddRange(conversations);
-            }
-            return conversationList.AsReadOnly();
+            return convs.ToList().AsReadOnly();
         }
 
         /// <summary>
@@ -485,5 +462,57 @@ namespace LeanCloud.Realtime {
             conversation = await GetConversation(convId);
             return conversation;
         }
+
+        internal async Task<IEnumerable<LCIMConversation>> GetOrQueryConversations(IEnumerable<string> ids) {
+            if (ids == null || ids.Count() == 0) {
+                return default;
+            }
+            
+            List<LCIMConversation> convs = new List<LCIMConversation>();
+            // 区分是否是缓存对话
+            IEnumerable<string> cachedConvIds = ids.Where(id => ConversationDict.ContainsKey(id));
+            IEnumerable<string> noCachedConvIds = ids.Except(cachedConvIds);
+
+            // 查找对话缓存
+            IEnumerable<LCIMConversation> cachedConvs = cachedConvIds.Select(id => {
+                return ConversationDict[id];
+            });
+            if (cachedConvs != null && cachedConvs.Count() > 0) {
+                convs.AddRange(cachedConvs);
+            }
+
+            // 区分临时对话
+            IEnumerable<LCIMConversation> queriedConvs = await QueryConversations(noCachedConvIds);
+            if (queriedConvs != null && queriedConvs.Count() > 0) {
+                convs.AddRange(queriedConvs);
+            }
+
+            return convs;
+        }
+
+        internal async Task<IEnumerable<LCIMConversation>> QueryConversations(IEnumerable<string> ids) {
+            if (ids == null || ids.Count() == 0) {
+                return default;
+            }
+
+            List<LCIMConversation> convs = new List<LCIMConversation>();
+            // 区分临时对话
+            IEnumerable<string> tempConvIds = ids.Where(item => {
+                return LCIMConversation.IsTemporayConversation(item);
+            });
+            IEnumerable<string> convIds = ids.Except(tempConvIds);
+            if (tempConvIds.Count() > 0) {
+                List<LCIMTemporaryConversation> temporaryConversations = await ConversationController.GetTemporaryConversations(tempConvIds);
+                convs.AddRange(temporaryConversations);
+            }
+            if (convIds.Count() > 0) {
+                LCIMConversationQuery query = GetQuery()
+                    .WhereContainedIn("objectId", convIds)
+                    .Limit(convIds.Count());
+                ReadOnlyCollection<LCIMConversation> conversations = await ConversationController.Find(query);
+                convs.AddRange(conversations);
+            }
+            return convs;
+        }
     }
 }