diff --git a/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/CountAPI.java b/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/CountAPI.java
index 43eaaada71..ecda4ad32d 100644
--- a/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/CountAPI.java
+++ b/hugegraph-api/src/main/java/com/baidu/hugegraph/api/traversers/CountAPI.java
@@ -141,7 +141,8 @@ public String toString() {
 
         private EdgeStep jsonToStep(HugeGraph graph) {
             return new EdgeStep(graph, this.direction, this.labels,
-                                this.properties, this.maxDegree, this.skipDegree);
+                                this.properties, this.maxDegree,
+                                this.skipDegree);
         }
     }
 }
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 0c85111d6c..3ec1362b8b 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
@@ -97,9 +97,10 @@ protected int concurrentDepth() {
         return this.graph.option(CoreOptions.OLTP_CONCURRENT_DEPTH);
     }
 
-    protected Set<Id> adjacentVertices(Set<Id> vertices, Directions dir,
-                                       Id label, Set<Id> excluded,
-                                       long degree, long limit) {
+    protected Set<Id> adjacentVertices(Id sourceV, Set<Id> vertices,
+                                       Directions dir, Id label,
+                                       Set<Id> excluded, long degree,
+                                       long limit) {
         if (limit == 0) {
             return ImmutableSet.of();
         }
@@ -111,7 +112,10 @@ protected Set<Id> adjacentVertices(Set<Id> vertices, Directions dir,
             while (edges.hasNext()) {
                 HugeEdge e = (HugeEdge) edges.next();
                 Id target = e.id().otherVertexId();
-                if (excluded != null && excluded.contains(target)) {
+                boolean matchExcluded = (excluded != null &&
+                                         excluded.contains(target));
+                if (matchExcluded || neighbors.contains(target) ||
+                    sourceV.equals(target)) {
                     continue;
                 }
                 neighbors.add(target);
@@ -376,8 +380,8 @@ public static void checkSkipDegree(long skipDegree, long degree,
         }
         if (skipDegree > 0L) {
             E.checkArgument(degree != NO_LIMIT && skipDegree >= degree,
-                            "The skipped degree must be >= degree, " +
-                            "but got skipped degree '%s' and degree '%s'",
+                            "The skipped degree must be >= max degree, " +
+                            "but got skipped degree '%s' and max degree '%s'",
                             skipDegree, degree);
         }
     }
diff --git a/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KneighborTraverser.java b/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KneighborTraverser.java
index 189394ec12..3403a53c25 100644
--- a/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KneighborTraverser.java
+++ b/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KneighborTraverser.java
@@ -47,15 +47,14 @@ public Set<Id> kneighbor(Id sourceV, Directions dir,
         Id labelId = this.getEdgeLabelId(label);
 
         Set<Id> latest = newSet();
-        latest.add(sourceV);
-
         Set<Id> all = newSet();
-        all.add(sourceV);
+
+        latest.add(sourceV);
 
         while (depth-- > 0) {
             long remaining = limit == NO_LIMIT ? NO_LIMIT : limit - all.size();
-            latest = this.adjacentVertices(latest, dir, labelId, all,
-                                           degree, remaining);
+            latest = this.adjacentVertices(sourceV, latest, dir, labelId,
+                                           all, degree, remaining);
             all.addAll(latest);
             if (limit != NO_LIMIT && all.size() >= limit) {
                 break;
diff --git a/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KoutTraverser.java b/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KoutTraverser.java
index f7a2a276f0..ec8e108c94 100644
--- a/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KoutTraverser.java
+++ b/hugegraph-core/src/main/java/com/baidu/hugegraph/traversal/algorithm/KoutTraverser.java
@@ -70,12 +70,12 @@ public Set<Id> kout(Id sourceV, Directions dir, String label,
                 remaining = limit;
             }
             if (nearest) {
-                latest = this.adjacentVertices(latest, dir, labelId, all,
-                                               degree, remaining);
+                latest = this.adjacentVertices(sourceV, latest, dir, labelId,
+                                               all, degree, remaining);
                 all.addAll(latest);
             } else {
-                latest = this.adjacentVertices(latest, dir, labelId, null,
-                                               degree, remaining);
+                latest = this.adjacentVertices(sourceV, latest, dir, labelId,
+                                               null, degree, remaining);
             }
             if (capacity != NO_LIMIT) {
                 // Update 'remaining' value to record remaining capacity