Objective To investigate the characteristics and risk factors of healthcare-associated infection(HAI) after open heart surgery, so as to provide theoretical basis for formulating intervention measures. Methods HAI in patients after open heart surgery in a tertiary heart hospital from January 1, 2016 to June 30, 2019 was investigated retrospectively, risk factors were analyzed. Results A total of 13 236 patients were investigated, 923 had post-opera-tive HAI, HAI rate was 6.97%. HAI rate varied with different surgical procedures, from high to low were complex cardiac surgery (13.32%), macrovascular surgery (11.60%), coronary artery transplantation (8.23%), valve surgery (5.49%), and simple cardiac surgery (5.45%). The main infection was lower respiratory tract infection (n=778, including 154 cases of ventilator-associated pneumonia), followed by upper respiratory tract infection (n=42), bloodstream infection (n=34), surgical site infection (n=27) and urinary tract infection (n=26). Multivariate logistic regression analysis showed that secondary surgery, allogeneic blood transfusion, duration of operation>265 minutes, and complex cardiac surgery were independent risk factors for HAI after open heart surgery. Conclusion Shortening operation time, reducing allogeneic blood transfusion and avoiding secondary surgery are beneficial to the prevention of HAI after open heart surgery.