diff --git a/pkg/controller/mysqlcluster/internal/syncer/healthy_replicas_service.go b/pkg/controller/mysqlcluster/internal/syncer/healthy_replicas_service.go
index 4c034de8d..2ec2d0942 100644
--- a/pkg/controller/mysqlcluster/internal/syncer/healthy_replicas_service.go
+++ b/pkg/controller/mysqlcluster/internal/syncer/healthy_replicas_service.go
@@ -17,6 +17,7 @@ limitations under the License.
 package mysqlcluster
 
 import (
+	"github.com/imdario/mergo"
 	"github.com/presslabs/controller-util/syncer"
 	core "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -41,9 +42,9 @@ func NewHealthyReplicasSVCSyncer(c client.Client, scheme *runtime.Scheme, cluste
 			service.Spec.Type = core.ServiceTypeLoadBalancer
 		}
 
-		// set annotations
-		if len(cluster.Spec.ReplicaServiceSpec.Annotations) > 0 {
-			service.ObjectMeta.Annotations = cluster.Spec.ReplicaServiceSpec.Annotations
+		// merge annotations
+		if err := mergo.Merge(&service.ObjectMeta.Annotations, cluster.Spec.ReplicaServiceSpec); err != nil {
+			return err
 		}
 
 		// set service labels
diff --git a/pkg/controller/mysqlcluster/internal/syncer/master_service.go b/pkg/controller/mysqlcluster/internal/syncer/master_service.go
index 541b89a2d..156e83904 100644
--- a/pkg/controller/mysqlcluster/internal/syncer/master_service.go
+++ b/pkg/controller/mysqlcluster/internal/syncer/master_service.go
@@ -17,6 +17,7 @@ limitations under the License.
 package mysqlcluster
 
 import (
+	"github.com/imdario/mergo"
 	"github.com/presslabs/controller-util/syncer"
 	core "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -41,9 +42,9 @@ func NewMasterSVCSyncer(c client.Client, scheme *runtime.Scheme, cluster *mysqlc
 			service.Spec.Type = core.ServiceTypeLoadBalancer
 		}
 
-		// set annotations
-		if len(cluster.Spec.MasterServiceSpec.Annotations) > 0 {
-			service.ObjectMeta.Annotations = cluster.Spec.MasterServiceSpec.Annotations
+		// merge annotations
+		if err := mergo.Merge(&service.ObjectMeta.Annotations, cluster.Spec.MasterServiceSpec.Annotations); err != nil {
+			return err
 		}
 
 		// set service labels