Abstract: Planetary protection is one of the key problems which will greatly affect the future human missions to Mars. Planetary protection has three major goals:1)The protection of extraterrestrial planet from terrestrial life contamination (forward contamination prevention);2) The protection of Earth from extraterrestrial life (back contamination prevention);3) The protection of the health and safety of astronauts. The international aerospace community has begun to formulate policies and conduct technical discussions on planetary protection for human Mars missions. In this review,the definition and legal base of planetary protection are introduced,and the planetary protection implementation of NASA Apollo program is reviewed,and the major contaminants,contamination pathway,and contamination control strategy for future human Mars missions are discussed.