Abstract: Planetary protection is a key problem with which each country conducting deep space exploration should face. The Mars is one of the celestial bodies that extraterrestrial life may exist,and is the major target for planetary protection. Before China start its own Mars exploration program,it is necessary to understand the policy,standard,techniques and management related to the planetary protection,in order to implement the planetary protection policies and requirements during the future Mars exploration practice. In this paper,the history of planetary protection is introduced,as well as the major control activities taken to prevent forward contamination in the previous Mars exploration programs,and the effects of modern scientific and technological development on the forward contamination prevention techniques of planetary protection. Some suggestions are provided on the planetary protection forward contamination control in China's Mars exploration program.