Regarding the timing of surgery for congenital heart disease ventricular septal defect, two factors are generally considered: on the one hand, the disease, the later the surgery, the more severe the disease progresses, the worse the surgical result; on the other hand, the patient’s problem, the later the surgery, the older the child, the stronger the resistance, the safer the surgery. So the best timing is the result of the comprehensive balance of these two. Generally can refer to the following principles: (1) because less than 5 mm membrane septal defect has the possibility of natural closure, and even if it does not heal on the human body is relatively small, surgery can be unnecessary, long-term observation, should be regular outpatient follow-up, once there are changes can be turned to surgery at any time. The vast majority of membrane ventricular septal defects larger than 6mm mm can be treated surgically at the age of about 1 year, when surgery is safer and not delayed because it leads to severe pulmonary hypertension. (2) Sub-stem ventricular septal defects, regardless of the size of the defect, should be operated on at or before 1 year of age to prevent aortic valve prolapse and having to surgically replace the aortic valve – that would seriously affect the quality of life. (3) Very few large ventricular defects (larger than 10 mm), recurrent pneumonia, and heart failure can be treated surgically as early as possible regardless of age, but the surgical risk is slightly greater.