Abstract: Objective To investigate the risk factors of pulmonary infection with Acinetobacter baumanii in patients after liver transplantation. Methods Clinical data about 343 patients who underwent liver transplantation in Beijing Chaoyang Hospital from January 2011 to December 2017 were retrospectively analyzed. According to the inclusion criteria, patients were divided into infection group (n=27) and control group (n=316). The general data, perioperative indicators and pulmonary infection with Acinetobacter baumanii were recorded and analyzed. Results In our research, pulmonary infection with Acinetobacter baumanii occurred in 27 cases with incidence of 7.9%, and five patients died of it. Multivariate analysis showed that neutrophil ratio, duration of mechanical ventilation and length of ICU stay were independent risk factors of infection (P< 0.05). Conclusion Neutrophil ratio, duration of mechanical ventilation and length of ICU stay are the main risk factors of pulmonary infection with Acinetobacter baumanii after liver transplantation.