Objective: To assess the efficacy and long-term outcome of percutaneous balloon aortic valvuloplasty (PBAV) for children with congenital aortic stenosis (CAS) and to explore risk factors for significant aortic regurgitation (AR) and reintervention after PBAV during follow up. Methods: This was a retrospective study. Children (≤18 years old) with CAS, who underwent PBAV in Guangdong Provincial Hospital from January 2004 to December 2018, were included in this study. Demographic, preoperative transthoracic echocardiography (TTE) and surgical data were collected. Postoperative complications were closely observed, and the patients were followed up at 1, 6, 12 months after the operation, and then at one year interval thereafter. Endpoint events included significant AR and reintervention. Reintervention was defined as any intervention that needed to be performed on the valve for various reasons, including re-PBAV, surgical valvuloplasty and valve replacement. Significant AR was defined as AR grade≥3 by TTE criteria. The results of the last TTE examination before the end of the study were collected. The Kaplan-Meier curve for long-term AR-free and intervention-free survival was plotted. Cox regression model was used to further analyze the risk factors for significant AR and reintervention after PBAV in CAS patients. Results: A total of 55 patients were enrolled in this study, and the age was 4.6(1.6, 6.5) years, with 37(67.3%) males. The peak systolic valve gradient fell from (80.3±30.6)mmHg to (38.5±18.5)mmHg(P<0.001, 1 mmHg=0.133 kPa). Surgical success rate was 89% (49/55). Acute post-PBAV AR occurred in 18 patients, including 3 patients with RA≥3 grade. In-hospital complications occurred in 6 patients (2 deaths, 2 cases of transient arrhythmia, and 2 cases of femoral artery embolization). Fifty patients accomplished the follow-up and the follow-up time was 6.2(3.4, 8.5) years. Significant AR was found in 20 patients. Significant AR-free survival rate was 53% at 5 years and 19% at 10 years. Reintervention was performed in 11 patients (4 with valvuloplasty and 7 with valve replacement), and the 5-year and 10-year intervention-free survival rates were 87% and 62%, respectively. Multivariate Cox regression analysis showed that acute post-PBAV AR was a risk factor for long-term significant AR (HR=2.398, 95%CI 1.007-5.712, P=0.048). Post-PBAV residual pressure gradient ≥ 35 mmHg (HR=4.747, 95%CI 1.116-19.329, P=0.030)and acute post-PBAV AR (HR=5.104, 95%CI 1.083-24.065, P=0.039)were risk factors for re-intervention. Conclusions: PBAV is safe and effective in the treatment of CAS in children, but attention should be paid on significant AR post procedure. Acute post-PBAV AR is a risk factor for re-intervention and significant AR post PBAV, and high post-PBAV residual pressure gradient is a risk factor for re-intervention.