Abstract: Interactive alpha matting technique extracts the foreground from an image or videos.In this paper, we survey the main interactive image and video matting algorithms in recent years.We analyze the performance of matting technique from propagation based methods, sampling based methods and geodesic based methods, and then discuss the advantages and limitations of different matting algorithms with examples.In the end, we conclude the development of matting technique and the key problems in the alpha matting technique.