diff --git a/server/gameserver/matchteam.cc b/server/gameserver/matchteam.cc
index 414b41c..654541d 100644
--- a/server/gameserver/matchteam.cc
+++ b/server/gameserver/matchteam.cc
@@ -111,7 +111,23 @@ bool MatchTeam::IsRawMember(const std::string &account_id)
 
 bool MatchTeam::IsValidMember(const cs::CMJoin& msg)
 {
-    return false;
+    if (msg.team_members().size() <= 0) {
+        return false;
+    }
+    if (first_member_->msg.team_uuid() != msg.team_uuid()) {
+        return false;
+    }
+    if (first_member_->msg.team_members().size() != msg.team_members().size()) {
+        return false;
+    }
+    for (int i = 0; i < msg.team_members().size(); ++i) {
+        auto& a = msg.team_members(i);
+        auto& b = first_member_->msg.team_members(i);
+        if (a.account_id() != b.account_id()) {
+            return false;
+        }
+    }
+    return true;
 }
 
 void MatchTeam::Update()