Thanks for your response . Great! It works when I published it to web page. But when I published in stand alone swf or win projector, it still appears jumpy. My friend told me to give flash player time to take a breath before doing his stuff using this: public class Main extends MovieClip { public function Main() { TweenLite.delayedCall(0.2, onTween, null); } public function onTween() { var obj:Object = { x:100, y:100, ease:Back.easeIn }; TweenLite.to(box_mc, 3, obj); } } It works well