Autostereoscopic display technique currently is in development stage. And it mainly is used in the commercial market and entertainment industry, so it is not used on a larger scale. From a technical point of view, free stereoscopic display can be divided into light barrier technology, cylindrical lens technology and point light source technology etc. Autostereoscopic display's biggest advantage is to get rid of the shackles of glasses. But there are many deficiencies in the resolution, visual angle and visual distance. This paper introduced the stereoscopic display technology and the advantages and disadvantages of various types of stereoscopic display technology in existence and the basic principle of stereo display. And it also introduced several freestereoscopic display technology and its implementation.