Abstract: OBJECTIVE To study the economic losses of hospitals and the military caused by Acinetobacter baumannii nosocomial infections, and provide management basis for the prevention and control of relevant departments in hospital. METHODS A retrospective investigation was conducted for the clinical data of the petients with A. baumannii nosocomial infections, including basic information, length of stay in hospital and hospitalization expenses from Jan 2016 to Dec 2020. The data were compared with those of patients with other bacterial infection. Frequency and composition ratio were used to describe the counting data; the median was used to describe the average level of hospitalization expenses and length of stay as well as its direct economic loss, and pairwise rank sum test was used to analyze the differences in hospitalization costs and length of stay between matched A. baumannii infections group（AB） and non-A. baumannii infections Group（NAB）. RESULTS The length of stay in hospital ranged from 3.98 to 42.95 days in the NAB group and from 9.90 to 118.05 days in the AB group. The individual hospitalization cost in patients of the NAB group was 4 207.25～222 417.69 yuan, the median was 34 240.24 yuan, and the total cost was 2 635 448.64 yuan. The total cost of individual hospitalization in the AB group was 6 939.74～ 75 809.83 yuan, the median was 103 409.49 yuan, and the total cost was 6 662 836.25 yuan. The direct economic loss in the AB group was 4 027 388.61 yuan more per year than that in the NAB group, and patients in the AB group spent an average of 69 169.25 yuan more per person. CONCLUSION The length of stay in the AB group was 7.46 days longer than that in the NAB group, hospitalization expenses in the AB group was twice as much as that in the NAB group. And the more the number of diseases diagnosed, the higher the total expenses cost. The economic loss caused by A. baumannii infections is huge, so it is urgent to strengthen the prevention and control of AB bacteria in the relevant departments of the hospital.