Five strains of lactic acid bacteria were isolated from tibet kefir.Two strains were identified preliminarily as Lactcbacillus acidophilus and three strains were identified preliminarily as Lactococcus lactis.Two strains of lactic acid bacteria were selected to study their probiotic properties.The results showed that two strains of lactic acid bacteria had good potential probiotics.Two strains of lactic acid bacteria could grow well at pH 4~6.Their high temperature resistance range was from 30 to 60℃.Bile tolerance was 0.1%~0.5%.Fermentation broth could inhibit intestinal pathogens and had different resistance against antibiotics.