Objective To investigate the risk factors for intraoperative delayed sternal closure (DSC) in infants with congenital heart disease (CHD).Method A retrospective analysis was conducted on 210 children with CHD (aged ≤ 12 months) who underwent median sternotomy and cardiopulmonary bypass (CPB) cardiac surgery in the Department of Pediatric Cardiothoracic Surgery of the First Affiliated Hospital of Xinjiang Medical University from January 1, 2016 to December 30, 2021. The patients were divided into two groups: 24 cases with delayed sternal closure (DSC) during the operation were assigned to the DSC group, and 186 cases with direct sternal closure during the operation were assigned to the direct sternal closure group. Univariate and multivariate Logistic general regression analyses were performed to identify the influencing factors of DSC in the children during the operation.Results The incidence of intraoperative DSC in infants with CHD was 11.4%. There were no significant differences in gender composition, premature birth rate, body mass index (BMI) and left ventricular ejection fractions (LVEF) between the DSC group and the direct sternal closure group (P > 0.05). There were statistically significant differences in age composition, modified ROSS score composition, E/e' value composition, pulmonary hypertension composition, risk adjustment for congenital heart surgery (RACHS-1) score composition, cardiothoracic ratio (CTR), operation time, CPB time and aortic cross-clamp (ACC) time between DSC group and direct sternal closure group (P < 0.05). Univariate general Logistic regression analysis showed that age ≤6 months, modified ROSS score ≥3, E/e' value >10, moderate to severe pulmonary hypertension, RACHS-1 score >3, increased operation time, CPB time ≥120 min and ACC time ≥60 min were statistically significant (P < 0.05). Multivariate general Logistic regression analysis showed that age ≤6 months [O^R =5.488 (95% CI: 1.795, 16.779) ], RACHS-1 score >3 [O^R =6.895 (95% CI: 2.171, 21.903) ], and CPB time ≥120 min [O^R =2.945 (95% CI: 1.058, 8.192) ] were all risk factors for intraoperative DSC.Conclusions age ≤6 months, RACHS-1 score >3, and CPB time ≥120 min are independent risk factors for intraoperative DSC in infants with CHD.