Objective To explore the effect of bed unit making on the number of bacteria in the air of wards. Methods In the surgical intensive care units where 10 bed units were made, the plate settling method was used to monitor and compare the airborne bacterial count and bacterial composition at 5 min before and 30 min after making bed units. Results The number of bacterial colonies in the air of the wards was not higher than 200.34 cfu / m³ at 5 min before the bed units were cleaned in all samples, and exceeded 200 cfu / m³ at 30 min after the bed units were cleaned in 80% samples. The number of bacterial colonies in the bed units after 30 min was significantly higher than that before 5 min of bed unit making. The number of airborne bacteria in the wards increased significantly after bed unit making, but the composition of bacteria did not change much. Conclusion Nurses need to pay attention to bed sweeping, ventilation, personnel activity control during making bed units, as well as subsequent disinfection and sterilization, to reduce the adverse effects of bed unit making on the number of airborne bacteria in the wards, thereby reducing nosocomial infection incidences.