diff --git a/hugegraph-common/src/main/java/org/apache/hugegraph/rest/AbstractRestClient.java b/hugegraph-common/src/main/java/org/apache/hugegraph/rest/AbstractRestClient.java
index 00662bf1..973f177d 100644
--- a/hugegraph-common/src/main/java/org/apache/hugegraph/rest/AbstractRestClient.java
+++ b/hugegraph-common/src/main/java/org/apache/hugegraph/rest/AbstractRestClient.java
@@ -127,6 +127,8 @@ private static RequestBody buildRequestBody(Object body, RestHeaders headers) {
         if (RestHeaders.APPLICATION_JSON.equals(contentType)) {
             if (body == null) {
                 bodyContent = "{}";
+            } else if (body instanceof String) {
+                bodyContent = (String) body;
             } else {
                 bodyContent = JsonUtilCommon.toJson(body);
             }