Abstract: Staphylococcus is one of pathogenic bacterium that inducing mastitis of dairy cow. In the research, 243 samples were collected from 18 dairy cow farms in Qinghai province. 86 Staphylococcus strains were isolated, including S.aureus 43 strains,S.xylosus and S.chromogenes 6 strains respectively, S.saproghyticus 5 strains, S.sciuri,S.cpidermidis and S.hominis 4 stains respectively, S.caplitis and S.simulans 2 trains respectively. The results indicated that S.aureus was primary pathogenic bacteria of Staphylococcus. All of Staphylococcus was hypersensitive to cephradine, amikacin and clindamycin, and partially resistant to enrofloxacin and gentamicin after K-B medicine sensitivity test.Collectively, the results laid the reference for selection of medicine to treat mastitis.

Key words: dairy cow; mastitis; Staphylococcus; medicine sensitivity test