Objective To understand the bacterial contamination of working clothes in medical institutions,and to evaluate the intervention effect by taking intervention measures. Methods A total of 10 medical staff uniforms were taken from 8 departments,including internal medicine department,surgery department,outpatient medical technology department and key departments.The cuffs,abdomen and pockets of clothes were sampled on the 1st,3rd,5th and 7th day after the replacement,and the bacterial were cultured. Results Before the both tervention,the bacterial exceeding rate of uniforms of medical staff on the 1st and 3rd day after wearing were both 0%.On the 5th and 7th day,the bacterial exceeding rate was 42.5% and 67.5% respectively.There was a significant difference in the unqualified rate among the four samples (χ²= 535.674,P＜0.001).With the increase of uniform wearing days,the bacterial exceeding rate increased (χ²_trend=481.329,P＜0.001).After intervention,the bacterial exceeding rate in uniforms of the medical staff were both 0%. Conclusion As the wearing time increased and the workplace was different,the degree of bacterial contamination in the uniforms of medical staff had increased.Medical institutions should establish reasonable uniform replacement cleaning frequency according to different risk level management in order to reduce cross-contamination of pathogenic bacteria and nosocomial infection.