The conventional surgery (CS) of supracardiac total anomalous pulmonary venous connection (TAPVC) is not always effective particularly in the setting of complex anatomy such as the mixed variety of TAPVC. This study aimed to analyze the outcomes of surgical treatment of supracardiac TAPVC and determine the optimal strategy. From December 2009 to December 2023, patients with supracardiac TAPVC undergoing surgical repair in our institution were included. The Kaplan-Meier curve was used to demonstrate the survival estimates. The Cox proportional hazard model was used to identify risk factors for death and postoperative pulmonary venous obstruction (PVO). One hundred and eighty-three patients with supracardiac TAPVC underwent surgical repair [CS group, n = 102; modified L-shaped incision technique (MLIT) group, n = 81]. There were 8 in-hospital deaths and 16 late deaths. The survival rates at 1, 5, and 10 years were 89.0%, 85.0%, and 85.0%, respectively in the whole cohort. Multivariable analysis showed that lower weight (P = 0.031), prolonged CBP time (P = 0.007), preoperative PVO (P = 0.020), and emergency surgery (P = 0.001) were incremental risk factors for death, but using the MLIT was a protective factor for death (p = 0.028). In the CS group, patients with emergency operation had worse survival than patients with elective surgery (P < 0.001). However, in the MLIT group, patients with emergency operation had comparable survival to patients with elective surgery (P = 0.332). Postoperative PVO occurred in 30 patients. Fourteen patients underwent PVO-related reintervention. In the whole cohort, freedom from postoperative PVO at 1, 5, and 10 years were 87.5%, 80.6%, and 80.6%, respectively. Patients who underwent MLIT repair had a lower incidence of postoperative PVO (P < 0.001), and PVO-related reintervention (P = 0.019). Neonates(P = 0.033), aortic cross-clamp time (P = 0.012), preoperative PVO (P = 0.002), and using the CS (P = 0.005) were associated with postoperative PVO. In terms of postoperative PVO, MLIT had a protective effect compared with CS. In the CS group, Infant and Children patients had better freedom from postoperative PVO than Neonate patients (P < 0.001). However, in the MLIT group, Neonate patients had comparable freedom from postoperative PVO to Infant and Children patients (P = 0.332). The MLIT can achieve satisfactory outcomes for supracardiac TAPVC repair. Compared with CS, the MLIT was significantly associated with decreased death, postoperative PVO, and PVO-related reintervention. It is especially significant in improving the survival rate of patients undergoing emergency surgery and reducing the incidence of postoperative PVO in neonatal patients.