ObjectiveTo compare the main hygiene indicators before and after clean operating rooms are used, evaluate the influencing factors, and find out the improvement measures.MethodsIn 2015, some cleaning operating rooms in Chengdu were detected, according to different service years and maintenance status, operating rooms were divided into newlybuilt group, replacement group, and nonreplacement group, change in qualified rate of three groups of clean operating room indicators were analyzed.ResultsA total of 111 cleaning operating rooms were detected, including 56 newlybuilt operating rooms, and 55 operating rooms (24 in replacement group,31 in nonreplacement group) which have been used for more than 1 years. The qualified rate of air cleanliness in newlybuilt group, replacement group, and nonreplacement group were 98.21%, 100.00%, and 74.19% respectively, difference among three groups was significantly(P<0.001）, the qualified rate of air cleanliness in newlybuilt group and replacement group were both higher than nonreplacement group, while newlybuilt group and replacement group was not significantly different(P=1.000）；difference in bacterial concentration, static pressure difference, and ventilation frequency of air in operating rooms of three groups were all not statistically significant(all P>0.05).ConclusionAfter clean operating room have been used for one year, air cleanliness declined, there was no significant change in static pressure difference and air exchange frequency, which indicates that when concentration of airborne bacteria is qualified, risk of infection due to unqualified air cleanliness still needs to be paid attention, the replacement of high efficiency particulate air filter in clean operating rooms can significantly improve the cleanliness of operating rooms.