diff --git a/server/apiv2/handlers/tso_keyspace_group.go b/server/apiv2/handlers/tso_keyspace_group.go
index 0e8c039d521..f5df812e428 100644
--- a/server/apiv2/handlers/tso_keyspace_group.go
+++ b/server/apiv2/handlers/tso_keyspace_group.go
@@ -135,6 +135,12 @@ func GetKeyspaceGroups(c *gin.Context) {
 	c.IndentedJSON(http.StatusOK, kgs)
 }
 
+// GetKeyspaceGroupPrimaryResponse defines the response for getting primary node of keyspace group.
+type GetKeyspaceGroupPrimaryResponse struct {
+	ID      uint32 `json:"id"`
+	Primary string `json:"primary"`
+}
+
 // GetKeyspaceGroupByID gets keyspace group by ID.
 func GetKeyspaceGroupByID(c *gin.Context) {
 	id, err := validateKeyspaceGroupID(c)
@@ -150,13 +156,17 @@ func GetKeyspaceGroupByID(c *gin.Context) {
 		return
 	}
 
-	if c.Query("get_param") == "primary" {
+	fields := c.Query("fields") // split by comma if need to add more fields
+	if fields == "primary" {
 		primary, err := manager.GetKeyspaceGroupPrimaryByID(id)
 		if err != nil {
 			c.AbortWithStatusJSON(http.StatusInternalServerError, err.Error())
 			return
 		}
-		c.JSON(http.StatusOK, primary)
+		c.JSON(http.StatusOK, &GetKeyspaceGroupPrimaryResponse{
+			ID:      id,
+			Primary: primary,
+		})
 		return
 	}
 
diff --git a/tests/pdctl/keyspace/keyspace_group_test.go b/tests/pdctl/keyspace/keyspace_group_test.go
index 50da5a3fd77..2ec200b0493 100644
--- a/tests/pdctl/keyspace/keyspace_group_test.go
+++ b/tests/pdctl/keyspace/keyspace_group_test.go
@@ -504,9 +504,9 @@ func TestShowKeyspaceGroupPrimary(t *testing.T) {
 		args := []string{"-u", pdAddr, "keyspace-group", "primary", defaultKeyspaceGroupID}
 		output, err := pdctl.ExecuteCommand(cmd, args...)
 		re.NoError(err)
-		addr := strings.ReplaceAll(string(output), "\"", "")
-		addr = strings.ReplaceAll(addr, "\n", "")
-		return s1.GetAddr() == addr || s2.GetAddr() == addr
+		var resp handlers.GetKeyspaceGroupPrimaryResponse
+		json.Unmarshal(output, &resp)
+		return s1.GetAddr() == resp.Primary || s2.GetAddr() == resp.Primary
 	})
 
 	// split keyspace group.
@@ -536,9 +536,9 @@ func TestShowKeyspaceGroupPrimary(t *testing.T) {
 		args := []string{"-u", pdAddr, "keyspace-group", "primary", "1"}
 		output, err := pdctl.ExecuteCommand(cmd, args...)
 		re.NoError(err)
-		addr := strings.ReplaceAll(string(output), "\"", "")
-		addr = strings.ReplaceAll(addr, "\n", "")
-		return s1.GetAddr() == addr || s2.GetAddr() == addr
+		var resp handlers.GetKeyspaceGroupPrimaryResponse
+		json.Unmarshal(output, &resp)
+		return s1.GetAddr() == resp.Primary || s2.GetAddr() == resp.Primary
 	})
 
 	re.NoError(failpoint.Disable("github.com/tikv/pd/pkg/keyspace/acceleratedAllocNodes"))
diff --git a/tools/pd-ctl/pdctl/command/keyspace_group_command.go b/tools/pd-ctl/pdctl/command/keyspace_group_command.go
index 3b75bdc9636..615251c31f3 100644
--- a/tools/pd-ctl/pdctl/command/keyspace_group_command.go
+++ b/tools/pd-ctl/pdctl/command/keyspace_group_command.go
@@ -357,7 +357,7 @@ func showKeyspaceGroupPrimaryCommandFunc(cmd *cobra.Command, args []string) {
 		cmd.Printf("Failed to parse the keyspace group ID: %s\n", err)
 		return
 	}
-	r, err := doRequest(cmd, fmt.Sprintf("%s/%s?get_param=primary", keyspaceGroupsPrefix, args[0]), http.MethodGet, http.Header{})
+	r, err := doRequest(cmd, fmt.Sprintf("%s/%s?fields=primary", keyspaceGroupsPrefix, args[0]), http.MethodGet, http.Header{})
 	if err != nil {
 		cmd.Printf("Failed to get the keyspace group primary information: %s\n", err)
 		return