Backrround Mortality in patients with acute myocardial infarction (AMI) undergoing an intra-aortic balloon pump (IABP) implantation remains high.This study aims to analyze the risk factors and subsequent prognostic impact of pulmonary infection in these populations.Methods Data of patients with AMI treated with the IABP between August 2017 and May 2018 was collected retrospectively.A total of 104 AMI patients who underwent the IABP and complicated with postoperative pulmonary infection were assigned to the observation group,meanwhile,73 patients without pulmonary:infection were chosen as the control group.The clinical characteristics were compared between two groups of patients,the risk factors and outcomes for the postoperative pulmonary infections were analyzed.Results Pulmonary infection can prolong CCU duration (11.7±8.2 vs.6.5±4.1,P＜0.001) and lead to higher in-hospital death (31.5％ vs.12.5％,P=0.002).Killip＞2 was an independent risk factor for pulmonary infection.In addition,multivariate logistic regression analysis indicated that Killip＞2,diabetes,current smoking,and pulmonary infection were independently associated with in-hospital death.Conclusions Postoperative pulmonary infection was a risk factor for poor outcomes in patients with AMI undergoing IABP.It is necessary to take corresponding interventions to reduce the risk of postoperative pulmonary infection.