diff --git a/src/main/java/com/actiontech/dble/services/mysqlsharding/MySQLShardingSQLHandler.java b/src/main/java/com/actiontech/dble/services/mysqlsharding/MySQLShardingSQLHandler.java
index c3bc997ab..ff4eb7539 100644
--- a/src/main/java/com/actiontech/dble/services/mysqlsharding/MySQLShardingSQLHandler.java
+++ b/src/main/java/com/actiontech/dble/services/mysqlsharding/MySQLShardingSQLHandler.java
@@ -48,6 +48,7 @@ public class MySQLShardingSQLHandler {
             try {
                 rrs = RouteService.getInstance().route(schemaConfig, type, sql, service);
                 if (rrs == null) {
+                    service.writeErrMessage(ErrorCode.ER_PARSE_ERROR, "The sql cannot be parsed to the specified node");
                     return;
                 }
                 if (rrs.getSqlType() == ServerParse.DDL && rrs.getSchema() != null) {
diff --git a/src/main/java/com/actiontech/dble/singleton/RouteService.java b/src/main/java/com/actiontech/dble/singleton/RouteService.java
index a216db8c6..396943c19 100644
--- a/src/main/java/com/actiontech/dble/singleton/RouteService.java
+++ b/src/main/java/com/actiontech/dble/singleton/RouteService.java
@@ -65,6 +65,8 @@ public final class RouteService {
                     rrs = HintPlanHandler.route(hintInfo.getHintValue(), sqlType, hintInfo.getRealSql());
                 } else if (type == DbleHintParser.DB_TYPE) {
                     rrs = HintMasterDBHandler.route(schema, hintInfo.getHintValue(), sqlType, hintInfo.getRealSql(), service);
+                } else {
+                    throw new SQLException("current hint type is not supported");
                 }
             }