Objective To explore the clinical curative effect of different timings of closed reduction and percutaneous pinning （CRPP） and its influences on complications in children with humeral supracondylar fractures. Methods In this retrospective study， a total of 100 children with humeral supracondylar fractures who underwent CRPP at the Affiliated Hospital of Xuzhou Medical University between February 2022 and February 2025 were enrolled. Based on the interval from injury to surgery， the children were divided into an early-treatment group （interval ≤ 12 hours， n = 58） and a delayed-treatment group （interval > 12 hours， n = 42）. The perioperative indexes and fracture healing time were compared between the two groups. Three months after surgery， the elbow range of motion on the affected side， Baumann angle， and carrying angle were evaluated. The clinical curative effect was assessed using the Flynn elbow scoring standard， and the incidence of complications was recorded. Results The operation time， intraoperative blood loss， and intraoperative fluoroscopy frequency in the early group were all significantly shorter or less than those in the delayed group （P < 0.05）. However， there was no significant difference in the length of hospital stay or fracture healing time between the two groups （P > 0.05）. Three months after surgery， there was no significant difference in the elbow range of motion， Baumann angle， or carrying angle between the two groups （P > 0.05）. The good-outcome rate of the early group was significantly higher than that of the delayed group （94.83% vs. 80.95%， P < 0.05）. The incidence of cubitus varus and the total incidence of complications in the early group were significantly lower than those in the delayed group （P < 0.05）. The results of univariate logistic regression analysis indicated that surgical timing， operation time， intraoperative blood loss， and intraoperative fluoroscopy frequency were all associated with the curative effect in children with humeral supracondylar fractures following CRPP （P < 0.05）. Multivariate logistic regression analysis demonstrated that early surgery was an independent protective factor for a good curative effect in children with humeral supracondylar fractures after CRPP （P < 0.05）. Conclusion Compared with delayed surgery， early CRPP （interval from injury to surgery ≤ 12 h） can significantly shorten the operation time， reduce the intraoperative blood loss， increase the good rate of elbow function， and reduce the risk of complications in children with humeral supracondylar fractures.