Objective To summarize our experience on leaflet extension in reoperation after tricuspid valve repair in children at age≤15 years and to explore the application indicators and skills of this technique. Methods We retrospectively analyzed the clinical data of 23 children who underwent reoperation after tricuspid valve repair in Xinhua Hospital between January 2006 and October 2015. There were 15 males and 8 females with a mean age of 8.7 years, ranging from 5 to 15 years. The leaflet was extended by artificial pericardium patch. After surgery, warfarin anticoagulation therapy was done, and international normalized ratio was maintained 2.0 to 3.0. Results The average cardiopulmonary bypass time was 87-132 (98.5±35.7) minutes, and average aortic cross-clamping time was 56-97 (68.40±23.78) minutes. One patient died in hospital. There were 3 patients with complications including respiratory failure in 1 patient, acute renal failure in 1 patient, and right heart insufficiency in 1 patient. All the children cured and were followed up for 5 months to 10 years, with a mean follow-up of 3.5 years. One patient died during the follow-up. Six patients suffered mild to moderate tricuspid regurgitation and tricuspid valve function of the rest patients was good. No other redo-valve surgery or complications correlated to anticoagulation occurred. Conclusion Leaflet extension in reoperation after tricuspid valve repair in children is useful with optimistic middle to long term efficacy and needs intensive care therapy during the perioperative period.