Abstract: Six strains probiotic lactic acid bacteria originated from yak Qula were used as the research objects,and their acid resistance,bile salt resistance,osmotic pressure resistance and inhibition ability were compared. The results showed that the six kinds of strains of lactic acid bacteria had different acid resistance,bile salt resistance,osmotic pressure resistance and inhibition ability. Strains G2,G4 and Q1 were best tolerant to acidic environments. Strains G2 and G4 had the strongest cholate tolerance. Strains G2,G4,and Q1 had strong resistance to high osmotic pressure. The survival rate of all strains in simulated gastrointestinal fluid were over 90%. Strain Q2 had the strongest antibacterial effect against Escherichia coli,followed by the strain Q1.Strain Q1 and Q2 had a better inhibitory effect on Staphylococcus aureus,followed by strain G2.Strain with the strongest antibacterial activity against Salmonella was strain Q2,and the worst antibacterial ability was strain G3.The strongest antibacterial activity against Listeria monocytogenes was the strain G4.The research results can provide a theoretical basis for the application of probiotic lactic acid.