Abstract: ObjectiveTo know drug-resistance and plasmid homology of SA in medical environment and provide data for controlling nosocomial infection in hospital environment.MethodsFive wards from two provincial hospitals in Lanzhou city were selected to collect different location samples randomly.Isolating,culturing,identifying and testing susceptibility of SA,plasmid elimination,plasmid profile and restriction endonuclease profile were used to analyze the homology.Results15 (7.7%)SA were isolated from 196 samples,the highest SA positive rate is air(19.1%).60.0% of SA isolated was resistant to PG and 4617% was resistant to more than three antibiotics.12(80.0%)strains of SA have plasmids between 1.06～39.93kb,3 strains have same resistance profile and similar plasmid profile from hospital B.Restriction endonuclease profile shows 4 strains have 5 same kinds of plasmid.ConclusionAir is the SA high risk transmit pathway and drug resistance is serious,homological drug-resistant plasmid exists in SA strains sampled from differenthospitals and different wards.