Objective    To analyze the cause of death in low-risk cardiac surgery patients during postoperative period and discuss the prevention and treatment methods to increase the survival rate. Methods    We retrospectively analyzed the clinical data of 132 patients dead after cardiac surgery from January 2014 to December 2018, among whom 35 patients had a EuroSCORE Ⅱ score <4% (low-risk cardiac surgery patients), including 20 males and 15 females aged 62.7±13.4 years. The cause of death in these low-risk patients was analyzed. Results    The main causes of death were cardiogenic and brain-derived causes (60.0%), and infections and ogran failure (45.7%). Pulmonary infection and low cardiac output after surgery were the main causes of death. Cerebral infarction, malignant arrhythmia and multiple organ failure were the common causes of death. There were 4 deaths (11.4%) caused by accidents, including gastrointestinal bleeding caused by esophageal ultrasound probe, cough and asphyxia caused by drinking water, postoperative paralytic ileus and multiple perioperative allergic reactions caused by allergic constitution. Conclusion    Postoperative treatment and prevention for low-risk cardiac surgery patients should be focused on postoperative infection, and cardiac and brain function protection. Changes in various organ functions need to be closely monitored for preventing organ failure, accidents should be strictly controlled, and more details of intraoperative and postoperative treatment still need to be further improved.