The so-called membrane septal tumor is not a real tumor, but a membrane septal defect or perimembranous septal defect, mostly located behind the tricuspid septal valve, and the defect opening is affected by blood flow and fibrous connective tissue adhesions, forming a tumor-like structure of the right ventricular septum convex to the right ventricle. If the septal defect does not close before the age of 3, it is very unlikely to heal on its own. If the defect is not treated, it is prone to infective endocarditis and damage to the heart valves because of the unstable blood flow in this area, and it is even more dangerous if there is valve stenosis, incomplete closure or redundancy. Most ventricular septal tumors can be treated with interventional blocking, and the rupture or the base can be blocked according to the intraoperative imaging to achieve a permanent cure. Li Fuhai, Department of Pediatrics, Qilu Hospital, Shandong University The arrow shows the shape, location and shunt flow of the ventricular septal tumor and the rupture opening. The septal blocker is applied to show the complete closure of the defect opening and the disappearance of the shunt flow.