Optical flow estimation is one of the important domains in computer vision. HS algorithm based on variational method is a classical optical flow estimation method, which can get consecutive smooth optical flow field in motion segmentation domain. But it usually takes a lot of time to calculate the HS model. In this paper, how HS algorithm gets optical flow field is analyzed firstly, and then a simplified HS algorithm is proposed, which does not need complex computation. Finally, Experiments demonstrate the validity and efficiency of the proposed method.