With the development of information technology, the importance of data backup becomes more important. But the traditional backup methods consume more resources and become managed difficultly. The emergence of virtualization technology breaks the traditional data backup methods. This paper describes several data backup mechanisms under the virtualization platform, and analyzes the advantage and disadvantages of each mechanism, so that the reader can choose the right backup solution according to the actual situation. Finally, the paper summarizes the virtualization backup mechanism problems and discusses the future trends.