Abstract: OBJECTIVE To explore the distribution of pathogens and influencing factors for pulmonary infection in the elderly patients after hip fracture surgery. METHODS Clinical data of 335 elderly patients underwent hip fracture surgery in the First People's Hospital of Lin'an from Jan 2020 to Apr 2022 were retrospectively collected. All patients were followed up for 30 days after surgery, and no case was lost. According to whether postoperative pulmonary infection occurred, the patients were divided into the pulmonary infection group (30 cases) and the non-pulmonary infection group (305 cases). The distribution of pathogens in the pulmonary infection group was analyzed, and the risk factors for pulmonary infection after hip fracture surgery in the elderly patients were analyzed by univariate and multivariate analysis. RESULTS The incidence of pulmonary infection after hip fracture surgery in the elderly patients was 8.96%. In the pulmonary infection group, 30 strains of pathogenic bacteria were isolated, including 18 strains of gram-negative bacteria (60.00%), 8 strains of gram-positive bacteria (26.67%) and 4 strains of fungi (13.33%). Age>70 years old, history of chronic obstructive pulmonary disease, high level of high-sensitivity C-reactive protein (hs-CRP) were risk factors for pulmonary infection after hip fracture surgery in the elderly patients (P＜0.05). CONCLUSION The incidence of pulmonary infection after hip fracture surgery is high in elderly patients, and the pathogenic bacteria are mainly gram-negative bacteria, which are closely related to the age of patients, history of chronic obstructive pulmonary disease, and hs-CRP level. Clinical prevention measures should be targeted to reduce the risk of pulmonary infection after hip fracture in elderly patients.