Objective To investigate the effect of tracheotomy on pulmonary infection and prognosis in patients with multiple trauma, and further analyze the independent risk factors of pulmonary infection in such patients. Methods Retrospective analysis was made on the clinical data of 43 patients with multiple injuries who underwent tracheotomy in our ICU from January 2019 to December 2021. The patients were divided into early tracheotomy group (within 7 days of injury) and late tracheotomy group (after 7 days of injury) according to the different tracheotomy time after injury. The differences between the two groups in 28 day mortality, lung infection, ventilator use time and ICU hospitalization time were compared; Further, the independent risk factors of pulmonary infection after tracheotomy were analyzed by single factor and multi factor binary logistic regression. Results 18 cases in the early tracheotomy group and 25 cases in the late tracheotomy group were included. It was found that there was no significant difference (P＞0.05) in the mortality of 28 days between the early tracheotomy group and the late tracheotomy group (16.7% vs 12.0%). the pulmonary infection rate in the early tracheotomy group was lower than that in the late tracheotomy group (33.3% vs72.0%), the difference was statistically significant (P＜0.05). the time of ventilator use in the early tracheotomy group was lower than that in the late tracheotomy group (14.7±6.8 vs 20.0±8.1), the difference was statistically significant (P＜0.05). the length of stay in ICU in the early tracheotomy group was lower than that in the late tracheotomy group (19.5±8.0 vs 26.8±12.1), with a statistically significant difference (P＜0.05). Univariate and multivariate binary logistic regression analysis showed that ISS score (OR=1.074, 95% CI:1.002～1.152, P=0.044), serum albumin (OR=0.722, 95% CI: 0.566～0.920, P=0.008), and smoking history (OR=0.139, 95% CI: 0.739～1.007, P=0.015) were independent risk factors for pulmonary infection after tracheotomy. Conclusion Early tracheotomy in patients with multiple injuries can reduce the rate of pulmonary infection, reduce the length of stay in ICU, and reduce the use of ventilators. ISS score, serum albumin and smoking history are independent risk factors for pulmonary infection after tracheotomy