Objective To summarize the reoperation experience for mitral regurgitation with leaflet augmentation in children. Methods From 2018 to 2022, the patients who underwent reoperation for mitral regurgitation with leaflet augmentation after atrioventricular septal defect repair or mitral valve repair in Fuwai Hospital were retrospectively collected. The characteristics of mitral valve disease, key points of surgery and short and mid-term follow-up results were analyzed. Results Finally 24 patients were enrolled, including 6 males and 12 females with an average age of 49.1±29.1 months. The time interval from the primary valve surgery to the reoperation was 24.9±17.0 months. The cardiopulmonary bypass time was 150.1±49.5 min and the aortic clamp time was 94.0±24.2 min. There was no early death. The average follow-up period was 20.3±9.1 months. During the follow-up period, the mortality rate was 4.2%, the rate of reoperation was 4.3%, and the rate of moderate or severe mitral regurgitation was 13.0%. The left ventricular ejection fraction was 62.6%±6.7%. In addition, the mean left ventricular end-diastolic dimension was 35.8±7.8 mm, which was significant smaller than that before the operation (t=4.858, P<0.000 1). Conclusion The application of leaflet augmentation is a safe and effective treatment option with good results in the short and mid-term, which thus provides a good technical option for pediatric patients with recurrent mitral regurgitation.