With the development of computer graphics, the models applied to agmented reality(AR) /virtual reality (VR) tend to be more complicated. Highly detailed representation without reducing frame rate either requires powerful computing devices or models with low complexity. The latter one is usually a more practical choice. Reducing the fineness of model to protect the AR/VR in real-time becomes a challenge. In this paper, a new method based on greedy assignment and Laplacian smoothing algorithm was introduced. Experimental results demonstrate that the proposed method has the least distortion under the same ratio of simplification, and can better meet the real-time requirements of AR/VR.