Whether it is a perimembranous ventricular septal defect or a subpulmonary ventricular septal defect, if the diameter is large, it is bound to cause a large amount of blood flow shunt from the left ventricle to the right ventricle, resulting in pulmonary hypertension and decreased cardiac function, and even death due to pneumonia and heart failure. For this group of children, early surgery is necessary to avoid complications and life-threatening conditions caused by ventricular septal defect and to improve the quality of life of the children. Currently, with the rapid improvement of cardiac surgery techniques and equipment, extracorporeal circulation, anesthesia, and postoperative monitoring, it is possible to repair ventricular septal defects in this group of children within one year of age. However, it is important to note that early surgery is also a prerequisite, i.e., the child must be operated on when the pneumonia is largely cured and the heart failure is largely resolved to ensure the success of the operation. For smaller diameter subpulmonary ventricular septal defects, if there are no obvious symptoms, it is recommended to complete the repair of the ventricular septal defect before the age of 1 year, because as the age increases, the aortic valve will also be affected by the ventricular septal defect and become diseased, which greatly increases the risk and difficulty of surgery. For smaller diameter perimembranous ventricular septal defects, surgical or interventional treatment is required if the defect does not “grow back” by school age. In medical centers where the surgical treatment of childhood precardiac disease is more common (e.g., Beijing Anzhen Hospital and Shanghai Children’s Medical Center), surgical repair of ventricular septal defects can be performed as young as one or two months (or even a few days after birth) if the condition requires it.