Introduction: Our aim was to investigate the incidence and risk factors for aortic regurgitation (AR) requiring unplanned surgery after transcatheter closure of ventricular septal defect (VSD) in children. Methods: Medical records of 876 children with VSD who underwent transcatheter closure from July 2009 to September 2018 in our hospital were retrospectively reviewed. Groups with and without new-onset or increasing AR requiring unplanned surgery were compared. Univariate and multivariate analyses were used to identify the possible risk factors. Smoothing plot and threshold effect analysis were carried out to find the relationship between possible factors and risk of new-onset or increasing AR. Results: A total of 29 children (3.3%) underwent unplanned surgery after transcatheter closure owing to new-onset or increasing AR, including 6 children with new-onset AR and 23 children with increasing AR. Multivariate regression analysis revealed that preoperative mild AR (OR: 60.39, 95% CI: 11.53–316.30, p < 0.001), larger ratio between diameter to body surface area (OR: 1.25, 95% CI: 1.01–1.55, p = 0.039), intracristal VSD (OR: 34.09, 95% CI: 4.07–285.65, p < 0.001), and shorter distance from the upper edge of defect to the aortic valve (or the sub-aortic rim) (OR: 0.12, 95% CI: 0.05–0.27, p < 0.001) were risk factors for new-onset or increasing AR requiring unplanned surgery. And, low risk of AR after muscular VSD transcatheter closure was found. An L-shaped nonlinear relationship between the sub-aortic rim and the risk of new-onset or increasing AR was observed, and the risk of new-onset or increasing AR with the sub-aortic rim up to the turning point (2 mm) (adjusted OR: 0.00, 95% CI: 0.00–0.08; p =0.001). With a median time of 7.3 years’ follow-up, no new-onset or increasing AR has been found for children who initially did not have unplanned surgery. Conclusion: Preoperative mild AR, larger ratio between diameter to body surface area, intracristal VSD, and shorter distance of the sub-aortic rim (especially <2 mm) could increase the risk of new-onset or increasing AR requiring unplanned surgery after transcatheter closure of VSD.