Abstract: As good probiotic bacteria,LAB(Lactic acid bacteria) have important physiological function to people,and LAB could survive in human gastro-intestinal tract was the basic premise of physiological function. The acid resistance of LAB was the result of combined action of multiple mechanisms,including TCS,outside and inside of the cell p H balance,the change of cell membrance,protein and DNA damage repair,bile salt resistance of LAB was related to its bile salt hydrolase and surface layer protein. Acid and bile salt resistance of LAB were studied by many reporters,and this paper summarized the mechanisms of acid and bile salt resistance of LAB basing on existed research results.