Abstract: High-precision time transfer technology is related to the development of positioning and navigation, high-speed communication, scientific research and other fields, and it is of great significance to carry out relevant research on it. Space laser time transfer is more accurate than based on microwave. Compared with time transfer technology via optical fiber, there is no need to build expensive special transmission channels, and it can be rapidly applied in the atmosphere, underwater and a variety of complex terrain, as well as temporary occasions, which breaks through the limitation of the transmission range and the application environment. Therefore, the research on laser time transfer technology has important practical significance and considerable development prospects. In this paper, four main schemes of laser time transfer in recent years are introduced, laser time transfer technology based on pulse time of flight measurement, laser time transfer technology integrated with communication, time transfer technology based on high speed pseudo code, and time transfer technology based on optical comb. The development status and trend of the four technological systems are sorted, which provides technical support for long distance and high precision time comparison.