diff --git a/cocos/3d/CCLight3D.cpp b/cocos/3d/CCLight3D.cpp
index ac77b3a50e..beb6e38cd1 100644
--- a/cocos/3d/CCLight3D.cpp
+++ b/cocos/3d/CCLight3D.cpp
@@ -76,9 +76,9 @@ const Vec3& DirectionLight3D::getDirection() const
     dir.set(-mat.m[8], -mat.m[9], -mat.m[10]);
     return dir;
 }
-Vec3 DirectionLight3D::getDirectionInWorld() const
+const Vec3& DirectionLight3D::getDirectionInWorld() const
 {
-    Vec3 dir;
+    static Vec3 dir;
     Mat4 mat = getNodeToWorldTransform();
     dir.set(-mat.m[8], -mat.m[9], -mat.m[10]);
     return dir;
@@ -139,9 +139,9 @@ const Vec3& SpotLight3D::getDirection() const
     return dir;
 }
 
-Vec3 SpotLight3D::getDirectionInWorld() const
+const Vec3& SpotLight3D::getDirectionInWorld() const
 {
-    Vec3 dir;
+    static Vec3 dir;
     Mat4 mat = getNodeToWorldTransform();
     dir.set(-mat.m[8], -mat.m[9], -mat.m[10]);
     return dir;
diff --git a/cocos/3d/CCLight3D.h b/cocos/3d/CCLight3D.h
index 717d17f2af..a964085798 100644
--- a/cocos/3d/CCLight3D.h
+++ b/cocos/3d/CCLight3D.h
@@ -126,7 +126,7 @@ public:
     /**
      * Returns direction in world.
      */
-    Vec3 getDirectionInWorld() const;
+    const Vec3& getDirectionInWorld() const;
     
 CC_CONSTRUCTOR_ACCESS:
     DirectionLight3D();
@@ -196,7 +196,7 @@ public:
     /**
      * Returns direction in world.
      */
-    Vec3 getDirectionInWorld() const;
+    const Vec3& getDirectionInWorld() const;
     
     /**
      * Sets the range of point or spot light.