diff --git a/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/HugeTraverser.java b/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/HugeTraverser.java
index 279064fcaa..d0b9852e40 100644
--- a/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/HugeTraverser.java
+++ b/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/HugeTraverser.java
@@ -87,7 +87,7 @@ public Set<Id> kout(Id sourceV, Directions dir, String label,
                         long degree, long capacity, long limit) {
         E.checkNotNull(sourceV, "source vertex id");
         E.checkNotNull(dir, "direction");
-        checkPositive(depth, "k-out depth");
+        checkPositive(depth, "k-out max_depth");
         checkDegree(degree);
         checkCapacity(capacity);
         checkLimit(limit);
@@ -143,7 +143,7 @@ public Set<Id> kneighbor(Id sourceV, Directions dir,
                              long degree, long limit) {
         E.checkNotNull(sourceV, "source vertex id");
         E.checkNotNull(dir, "direction");
-        checkPositive(depth, "k-neighbor depth");
+        checkPositive(depth, "k-neighbor max_depth");
         checkDegree(degree);
         checkLimit(limit);