Objective To explore the risk factors and countermeasures of the perfusionist-related near-miss event (NME) in cardiopulmonary bypass (CPB). Methods The clinical data of the patients who underwent cardiac surgery in the Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University from March 2020 to July 2021 were retrospectively analyzed. According to whether NME occurred during the operation, the patients were divided into an NME group and a non-NME group. The clinical data of the two groups were compared, and the risk factors for NME were analyzed. Results A total of 702 patients were enrolled, including 424 males and 278 females with a median age of 56.0 years. There were 125 patients in the NME group and 577 patients in the non-NME group. The occurrence rate of NME was 17.81%. Univariate analysis showed that there were statistical differences between the two groups in the gender, body surface area, CPB time, European system for cardiac operative risk evaluation score, emergency surgery, type of surgery, night CPB initiation, modified ultrafiltration use, multi-device control, average operation time, et al. (all P<0.05). The above variables were dimensionality reduction processed by least absolute shrinkage and selection operator regression, and the λ of minimum mean square error of 10-fold cross validation was 0.014. The variables of the corresponding model were selected as follows: multi-device control, night CPB initiation, minimum hematocrit, modified ultrafiltration use, CPB time. The results of multivariate logistic regression showed that night CPB initiation [OR=9.658, 95%CI (4.735. 19.701), P<0.01] and CPB time [OR=1.003, 95%CI (1.001, 1.006), P=0.014] were independent risk factors for NME. Conclusion Night CPB initiation and CPB time are independent risk factors for NME during CPB, which should be recognized and early warned in clinical work.