Background　 Increasing evidences have showed that several pattern of preconditioning can induce endogenous tolerance to secondary injuries..The protective effect of hypobaric hypoxia preconditioning(HHP) have been proved by lots of experiments.　Objective　The review elaborates protection of HHP and its mechanism by summarizing studies and researches in recent years.　Content　HHP can induce endogenous tolerance to resisting anxiety and depression,regulating immune homeostasis,reducing the damage of severe hypoxia and ischemia and reperfusion(I/R).The mechanism of endogenous tolerance are involved in reactive oxygen species(ROS), Heat shock proteins(HSPs), estrogen,apoptosis and signaling pathway,etc.　Trend　Researches in future should be taken to further explore of the mechanism of hypobaric hypoxia preconditioning,and establish a appropriate HHP methods having no damages to tissues.Strengthening the clinical applications of HHP will also be helpful to provide a reliable basis for the practice work.