ObjectiveTo evaluate air quality of a dental clinic in the state of working.MethodsAir of a dental clinic was disinfected by air disinfector twice a day for consecutive 30 days, disinfection was performed at 7∶00 AM and 13∶00 PM for 1 hour respectively, air samples in the state of working (once an hour between 8∶00AM17∶00PM, 13∶00PM excluded) were collected, and bacterial colonies were counted. ResultsThe average bacteria count were (275.70±81.87) CFU/m3 at 8∶00 AM, (411.80±175.66) CFU/m3(968.10±204.14) CFU/m3 at 9∶00 AM17∶00 PM. Air quality was in line with the Technical Standard for Disinfection at static state after disinfection, bacterial colony significantly exceeded standard with the extension of working hours.ConclusionIn order to ensure air quality of dental clinic in the state of working in line with national regulatory requirements, dynamic disinfection measures are recommended.