Abstract: In order to draw smooth shadow and enhance the reality in virtual scene,we present a GPU based real-time method to realize shadow smoothing of coarse meshes.We compute the accurate silhouette of the mesh by redefining the shadow silhouette.Then we apply the shadow volume method to get the shadow region with smooth contour.We utilize GPU to accelerate the process of computing the silhouette and the rendering of shadow.The experiment results show that our method has better effect and the rendering speed is superior to the existing methods as well.