目的　了解新生儿重症监护室 (NICU)内进行医疗活动总人数及不同医疗护理活动对空气细菌菌落数的影响。　方法　采用空气自然沉降法观察每小时空气细菌菌落数 ,同时记录相应时间病室内总人数及其活动内容 ,并研究其影响因素及它们之间的相关性。　结果　两次观察的 17组室内空气细菌菌落数的最高值为 (14 4 7± 38)cfu/平板 ,最低值为 (2 0 5± 14 )cfu/平板 ,均值为 (5 0 0± 2 2 )cfu/平板 ,中位数为 346。经过对不同分类因素相应细菌菌落数之间差异u检验及相关系数检测 ,病室内细菌菌落数的改变与人员流动数呈良好的正相关性 (r =0 .78,P <0 .0 1) ,病室内不同活动内容中 ,技术员做检查 (r=0 .77,P <0 .0 1)及护理活动 (r =0 .6 4 ,P <0 .0 1)相关性大 ,差异有显著性 ;而与洁净器的开关状态相关性极差 (r = 0 .2 0 ,P =0 .36 )。　结论　空气细菌菌落数与室内人员总数、室内进行检查操作和护理活动关系密切。洁净器的使用与室内空气细菌菌落数之间的关系有待进一步研究。 Objectives To understand the total number of medical activities performed in neonatal intensive care units (NICU) and the impact of different medical care activities on the number of airborne bacterial colonies. Methods The number of airborne bacterial colonies per hour was observed by air natural sedimentation method. The total number of wards and their activities at the corresponding time were recorded. The influencing factors and their correlations were also studied. Results The highest number of bacterial colonies in indoor air was observed in 17 groups (1447 ± 38) cfu per plate and the lowest was (205 ± 14) cfu per plate, with a mean of (500 ± 2 2 ) cfu / plate, median 346. After the differences in the number of bacterial colonies between the different classification factors u test and correlation coefficient detection, the number of bacterial colonies in the ward and the number of staff flow was positively correlated (r = 0.78, P <0.01) (R = 0.77, P <0.01) and nursing activities (r = 0.64, P <0.01) in the different activities of the ward, the difference was significant But was not related to the switch state of the cleaner (r = 0.20, P = 0.36). Conclusion The number of airborne bacterial colonies is closely related to the total number of indoor staff, indoor inspection operations and nursing activities. The relationship between the use of cleaner and the number of bacterial colonies of indoor air needs further study.