diff --git a/tests/integrations/mcs/tso/keyspace_group_manager_test.go b/tests/integrations/mcs/tso/keyspace_group_manager_test.go
index 1436441f2c67..c35723236e83 100644
--- a/tests/integrations/mcs/tso/keyspace_group_manager_test.go
+++ b/tests/integrations/mcs/tso/keyspace_group_manager_test.go
@@ -379,8 +379,8 @@ func (suite *tsoKeyspaceGroupManagerTestSuite) TestTSOKeyspaceGroupSplitClient()
 	re.Equal(uint32(1), kg1.ID)
 	re.Equal([]uint32{111, 222, 333}, kg1.Keyspaces)
 	re.False(kg1.IsSplitting())
-	// Make sure the leader of the keyspace group 2 is elected.
-	member, err := suite.tsoCluster.WaitForPrimaryServing(re, 222, 2).GetMember(222, 2)
+	// Make sure the leader of the keyspace group 1 is elected.
+	member, err := suite.tsoCluster.WaitForPrimaryServing(re, 222, 1).GetMember(222, 1)
 	re.NoError(err)
 	re.NotNil(member)
 	// Prepare the client for keyspace 222.
@@ -630,3 +630,84 @@ func (suite *tsoKeyspaceGroupManagerTestSuite) TestTSOKeyspaceGroupMerge() {
 	}, testutil.WithTickInterval(5*time.Second), testutil.WithWaitFor(time.Minute))
 	re.Greater(tsoutil.CompareTimestamp(&mergedTS, &ts), 0)
 }
+
+func (suite *tsoKeyspaceGroupManagerTestSuite) TestTSOKeyspaceGroupMergeClient() {
+	re := suite.Require()
+	// Create the keyspace group 1 with keyspaces [111, 222, 333].
+	handlersutil.MustCreateKeyspaceGroup(re, suite.pdLeaderServer, &handlers.CreateKeyspaceGroupParams{
+		KeyspaceGroups: []*endpoint.KeyspaceGroup{
+			{
+				ID:        1,
+				UserKind:  endpoint.Standard.String(),
+				Members:   suite.tsoCluster.GetKeyspaceGroupMember(),
+				Keyspaces: []uint32{111, 222, 333},
+			},
+		},
+	})
+	kg1 := handlersutil.MustLoadKeyspaceGroupByID(re, suite.pdLeaderServer, 1)
+	re.Equal(uint32(1), kg1.ID)
+	re.Equal([]uint32{111, 222, 333}, kg1.Keyspaces)
+	re.False(kg1.IsMerging())
+	// Make sure the leader of the keyspace group 1 is elected.
+	member, err := suite.tsoCluster.WaitForPrimaryServing(re, 222, 1).GetMember(222, 1)
+	re.NoError(err)
+	re.NotNil(member)
+	// Prepare the client for keyspace 222.
+	tsoClient, err := pd.NewClientWithKeyspace(suite.ctx, 222, []string{suite.pdLeaderServer.GetAddr()}, pd.SecurityOption{})
+	re.NoError(err)
+	re.NotNil(tsoClient)
+	// Request the TSO for keyspace 222 concurrently.
+	var (
+		wg                        sync.WaitGroup
+		ctx, cancel               = context.WithCancel(suite.ctx)
+		lastPhysical, lastLogical int64
+	)
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for {
+			select {
+			case <-ctx.Done():
+				// Make sure at least one TSO request is successful.
+				re.NotEmpty(lastPhysical)
+				return
+			default:
+			}
+			physical, logical, err := tsoClient.GetTS(ctx)
+			if err != nil {
+				errMsg := err.Error()
+				// Ignore the errors caused by the merge and context cancellation.
+				if strings.Contains(errMsg, "context canceled") ||
+					strings.Contains(errMsg, "not leader") ||
+					strings.Contains(errMsg, "not served") ||
+					strings.Contains(errMsg, "ErrKeyspaceNotAssigned") ||
+					strings.Contains(errMsg, "ErrKeyspaceGroupIsMerging") {
+					continue
+				}
+				re.FailNow(errMsg)
+			}
+			if physical == lastPhysical {
+				re.Greater(logical, lastLogical)
+			} else {
+				re.Greater(physical, lastPhysical)
+			}
+			lastPhysical, lastLogical = physical, logical
+		}
+	}()
+	// Merge the keyspace group 1 to the default keyspace group.
+	handlersutil.MustMergeKeyspaceGroup(re, suite.pdLeaderServer, mcsutils.DefaultKeyspaceGroupID, &handlers.MergeKeyspaceGroupsParams{
+		MergeList: []uint32{1},
+	})
+	// Wait for the default keyspace group to finish the merge.
+	testutil.Eventually(re, func() bool {
+		kg := handlersutil.MustLoadKeyspaceGroupByID(re, suite.pdLeaderServer, mcsutils.DefaultKeyspaceGroupID)
+		re.Equal(mcsutils.DefaultKeyspaceGroupID, kg.ID)
+		for _, keyspaceID := range []uint32{111, 222, 333} {
+			re.Contains(kg.Keyspaces, keyspaceID)
+		}
+		return !kg.IsMergeTarget()
+	})
+	// Stop the client.
+	cancel()
+	wg.Wait()
+}