Abstract: OBJECTIVE To analyze characteristics, influencing factors and prognosis of Stenotrophomonas maltophilia nosocomial infections, so as to provide theoretical basis for the clinical prevention and control of S. maltophilia infection. METHODS Totally 422 patients infected by S. maltophilia were collected in the Fifth Medical Center of the PLA from Dec. 2014 to Aug. 2018, and then a retrospective study was carried out to analyze the specimens, departments, infection sites and influencing factors of the patients. RESULTS The top five specimens sources were the sputum（75.36%）, alveolar lavage fluid（7.58%）, throat swabs（5.69%）, blood（4.74%） and secretions（4.50%）. The top five departments were critical care medicine department（45.73%）, hematology department（17.54%）, transplantation department（9.72%） and oncology department（6.87%）. Lower respiratory tract infections were the most common（88.39%, 373/422）. Tracheal intubation or incision, indwelling urinary catheter and basic pulmonary diseases were the influencing factors of S. maltophilia infection in patients with lower respiratory tract infection（P＜0.05）. CONCLUSION It is an effective way to reduce the rate of lower respiratory infection induced by S. maltophilia by strengthening the implementation of infection prevention and control measures for patients with underlying pulmonary diseases, tracheal intubation or incision and indwelling urinary catheters.