diff --git a/client/client.go b/client/client.go
index e95639473..c19a1ec43 100644
--- a/client/client.go
+++ b/client/client.go
@@ -249,14 +249,14 @@ func (cli *TMSPClient) GetHashSync() (hash []byte, log string, err error) {
 	return res.Data, res.Log, nil
 }
 
-func (cli *TMSPClient) QuerySync(query []byte) (result []byte, log string, err error) {
+func (cli *TMSPClient) QuerySync(query []byte) (code types.RetCode, result []byte, log string, err error) {
 	reqres := cli.queueRequest(types.RequestQuery(query))
 	cli.FlushSync()
 	if cli.err != nil {
-		return nil, "", cli.err
+		return types.RetCodeInternalError, nil, "", cli.err
 	}
 	res := reqres.Response
-	return res.Data, res.Log, nil
+	return types.RetCode(res.Code), res.Data, res.Log, nil
 }
 
 //----------------------------------------
diff --git a/example/golang/counter.go b/example/golang/counter.go
index 962c0760b..120eb3189 100644
--- a/example/golang/counter.go
+++ b/example/golang/counter.go
@@ -66,6 +66,6 @@ func (app *CounterApplication) GetHash() (hash []byte, log string) {
 	}
 }
 
-func (app *CounterApplication) Query(query []byte) (result []byte, log string) {
-	return nil, fmt.Sprintf("Query is not supported")
+func (app *CounterApplication) Query(query []byte) (code types.RetCode, result []byte, log string) {
+	return types.RetCodeOK, nil, fmt.Sprintf("Query is not supported")
 }
diff --git a/example/golang/dummy.go b/example/golang/dummy.go
index 9835eeb81..59d77dc32 100644
--- a/example/golang/dummy.go
+++ b/example/golang/dummy.go
@@ -40,6 +40,6 @@ func (app *DummyApplication) GetHash() (hash []byte, log string) {
 	return hash, ""
 }
 
-func (app *DummyApplication) Query(query []byte) (result []byte, log string) {
-	return nil, "Query not supported"
+func (app *DummyApplication) Query(query []byte) (code types.RetCode, result []byte, log string) {
+	return types.RetCodeOK, nil, "Query not supported"
 }
diff --git a/server/server.go b/server/server.go
index 74b4ce74c..b95f9e8bb 100644
--- a/server/server.go
+++ b/server/server.go
@@ -116,8 +116,8 @@ func handleRequest(app types.Application, req *types.Request, responses chan<- *
 		hash, logStr := app.GetHash()
 		responses <- types.ResponseGetHash(hash, logStr)
 	case types.RequestTypeQuery:
-		result, logStr := app.Query(req.Data)
-		responses <- types.ResponseQuery(result, logStr)
+		code, result, logStr := app.Query(req.Data)
+		responses <- types.ResponseQuery(code, result, logStr)
 	default:
 		responses <- types.ResponseException("Unknown request")
 	}
diff --git a/types/application.go b/types/application.go
index cedf12405..0610d4182 100644
--- a/types/application.go
+++ b/types/application.go
@@ -18,5 +18,5 @@ type Application interface {
 	GetHash() (hash []byte, log string)
 
 	// Query for state
-	Query(query []byte) (result []byte, log string)
+	Query(query []byte) (code RetCode, result []byte, log string)
 }
diff --git a/types/messages.go b/types/messages.go
index 8c21f327c..061d34da6 100644
--- a/types/messages.go
+++ b/types/messages.go
@@ -125,6 +125,7 @@ func ResponseSetOption(log string) *Response {
 func ResponseAppendTx(code RetCode, result []byte, log string) *Response {
 	return &Response{
 		Type: ResponseTypeAppendTx,
+		Code: uint32(code),
 		Data: result,
 		Log:  log,
 	}
@@ -133,6 +134,7 @@ func ResponseAppendTx(code RetCode, result []byte, log string) *Response {
 func ResponseCheckTx(code RetCode, result []byte, log string) *Response {
 	return &Response{
 		Type: ResponseTypeCheckTx,
+		Code: uint32(code),
 		Data: result,
 		Log:  log,
 	}
@@ -146,9 +148,10 @@ func ResponseGetHash(hash []byte, log string) *Response {
 	}
 }
 
-func ResponseQuery(result []byte, log string) *Response {
+func ResponseQuery(code RetCode, result []byte, log string) *Response {
 	return &Response{
 		Type: ResponseTypeQuery,
+		Code: uint32(code),
 		Data: result,
 		Log:  log,
 	}