diff --git a/internal/querycoordv2/server.go b/internal/querycoordv2/server.go
index cd39e25c75..54f93b85c5 100644
--- a/internal/querycoordv2/server.go
+++ b/internal/querycoordv2/server.go
@@ -649,11 +649,7 @@ func (s *Server) handleNodeUp(node int64) {
 		zap.String("resourceGroup", rgName),
 	)
 
-	rgs := s.meta.ResourceManager.ListResourceGroups()
-	if len(rgs) == 1 {
-		// only __default_resource_group exists
-		utils.AddNodesToCollectionsInRG(s.meta, meta.DefaultResourceGroupName, node)
-	}
+	utils.AddNodesToCollectionsInRG(s.meta, meta.DefaultResourceGroupName, node)
 }
 
 func (s *Server) handleNodeDown(node int64) {
diff --git a/internal/querycoordv2/services.go b/internal/querycoordv2/services.go
index df69713608..f34dd5ac1b 100644
--- a/internal/querycoordv2/services.go
+++ b/internal/querycoordv2/services.go
@@ -1095,7 +1095,14 @@ func (s *Server) TransferReplica(ctx context.Context, req *querypb.TransferRepli
 			fmt.Sprintf("the target resource group[%s] doesn't exist", req.GetTargetResourceGroup()), meta.ErrRGNotExist), nil
 	}
 
-	replicas := s.meta.ReplicaManager.GetByCollectionAndRG(req.GetCollectionID(), req.GetTargetResourceGroup())
+	replicas := s.meta.ReplicaManager.GetByCollection(req.GetCollectionID())
+	if (req.GetSourceResourceGroup() == meta.DefaultResourceGroupName || req.GetTargetResourceGroup() == meta.DefaultResourceGroupName) &&
+		len(replicas) != int(req.GetNumReplica()) {
+		return utils.WrapStatus(commonpb.ErrorCode_IllegalArgument,
+			"transfer replica will cause replica loaded in both default rg and other rg", nil), nil
+	}
+
+	replicas = s.meta.ReplicaManager.GetByCollectionAndRG(req.GetCollectionID(), req.GetTargetResourceGroup())
 	if len(replicas) > 0 {
 		return utils.WrapStatus(commonpb.ErrorCode_IllegalArgument,
 			fmt.Sprintf("found [%d] replicas of same collection in target resource group[%s], dynamically increase replica num is unsupported",
diff --git a/internal/querycoordv2/services_test.go b/internal/querycoordv2/services_test.go
index bd666e8af9..524f00404b 100644
--- a/internal/querycoordv2/services_test.go
+++ b/internal/querycoordv2/services_test.go
@@ -600,7 +600,7 @@ func (suite *ServiceSuite) TestTransferReplica() {
 	suite.NoError(err)
 
 	resp, err := suite.server.TransferReplica(ctx, &querypb.TransferReplicaRequest{
-		SourceResourceGroup: meta.DefaultResourceGroupName,
+		SourceResourceGroup: "rg2",
 		TargetResourceGroup: "rg1",
 		CollectionID:        1,
 		NumReplica:          2,
@@ -608,6 +608,15 @@ func (suite *ServiceSuite) TestTransferReplica() {
 	suite.NoError(err)
 	suite.Contains(resp.Reason, "only found [0] replicas in source resource group")
 
+	resp, err = suite.server.TransferReplica(ctx, &querypb.TransferReplicaRequest{
+		SourceResourceGroup: meta.DefaultResourceGroupName,
+		TargetResourceGroup: "rg1",
+		CollectionID:        1,
+		NumReplica:          2,
+	})
+	suite.NoError(err)
+	suite.Contains(resp.Reason, "transfer replica will cause replica loaded in both default rg and other rg")
+
 	resp, err = suite.server.TransferReplica(ctx, &querypb.TransferReplicaRequest{
 		SourceResourceGroup: "rgg",
 		TargetResourceGroup: meta.DefaultResourceGroupName,
@@ -655,26 +664,29 @@ func (suite *ServiceSuite) TestTransferReplica() {
 	suite.server.nodeMgr.Add(session.NewNodeInfo(1002, "localhost"))
 	suite.server.nodeMgr.Add(session.NewNodeInfo(1003, "localhost"))
 	suite.server.nodeMgr.Add(session.NewNodeInfo(1004, "localhost"))
+	suite.server.nodeMgr.Add(session.NewNodeInfo(1005, "localhost"))
 	suite.server.meta.AssignNode("rg1", 1001)
 	suite.server.meta.AssignNode("rg2", 1002)
 	suite.server.meta.AssignNode("rg3", 1003)
 	suite.server.meta.AssignNode("rg3", 1004)
+	suite.server.meta.AssignNode("rg3", 1005)
 
+	replicaNum := len(suite.server.meta.ReplicaManager.GetByCollection(1))
 	resp, err = suite.server.TransferReplica(ctx, &querypb.TransferReplicaRequest{
 		SourceResourceGroup: meta.DefaultResourceGroupName,
 		TargetResourceGroup: "rg3",
 		CollectionID:        1,
-		NumReplica:          2,
+		NumReplica:          int64(replicaNum),
 	})
 
 	suite.NoError(err)
 	suite.Equal(resp.ErrorCode, commonpb.ErrorCode_Success)
-	suite.Len(suite.server.meta.GetByResourceGroup("rg3"), 2)
+	suite.Len(suite.server.meta.GetByResourceGroup("rg3"), 3)
 	resp, err = suite.server.TransferReplica(ctx, &querypb.TransferReplicaRequest{
 		SourceResourceGroup: meta.DefaultResourceGroupName,
 		TargetResourceGroup: "rg3",
 		CollectionID:        1,
-		NumReplica:          2,
+		NumReplica:          int64(replicaNum),
 	})
 	suite.NoError(err)
 	suite.Contains(resp.Reason, "dynamically increase replica num is unsupported")
@@ -1604,8 +1616,9 @@ func (suite *ServiceSuite) TestHandleNodeUp() {
 	suite.nodeMgr.Add(session.NewNodeInfo(222, "localhost"))
 	server.handleNodeUp(222)
 	nodes = suite.server.meta.ReplicaManager.Get(1).GetNodes()
-	suite.Len(nodes, 1)
-	suite.Equal(int64(111), nodes[0])
+	suite.Len(nodes, 2)
+	suite.Contains(nodes, int64(111))
+	suite.Contains(nodes, int64(222))
 }
 
 func (suite *ServiceSuite) loadAll() {