diff --git a/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/NeighborRankAPI.java b/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/NeighborRankAPI.java
index 3ad6bc58f1..198e13f28b 100644
--- a/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/NeighborRankAPI.java
+++ b/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/NeighborRankAPI.java
@@ -101,7 +101,7 @@ private static List<NeighborRankTraverser.Step> steps(HugeGraph graph,
     private static class RankRequest {
 
         @JsonProperty("source")
-        private String source;
+        private Object source;
         @JsonProperty("steps")
         private List<Step> steps;
         @JsonProperty("alpha")
diff --git a/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/PersonalRankAPI.java b/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/PersonalRankAPI.java
index f715055683..60d2386e57 100644
--- a/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/PersonalRankAPI.java
+++ b/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/PersonalRankAPI.java
@@ -101,7 +101,7 @@ public String personalRank(@Context GraphManager manager,
     private static class RankRequest {
 
         @JsonProperty("source")
-        private String source;
+        private Object source;
         @JsonProperty("label")
         private String label;
         @JsonProperty("alpha")