Abstract: The sixteen 16 strains of lactic acid bacteria were isolated from the cow milk in the Damao pasture of Inner Mongolia,and were used as research subjects in the study. The method of morphological observation,biological characteristics test and 16 S r RNA identification were adopted in the experiment. The disk diffusion method was used to determine drug resistance of three antibiotics of amoxicillin,ampicillin and erythromycin.Results showed that DM8 was Lactococcus lactis,and DM21 was Lactobacillus,and that except DM8 and DM21,the rest were all Lactobacillus plantarum.The study also showed that the tested strains resistant to amoxicillin was12.5%,the tested strains were sensitive to ampicillin and erythromycin,and the sensitive strain was not entirely safety strain through analysis.