The causes of congenital heart disease are still a minority, and about 90% of the causes are not very clear, and are related to many factors, which are multiple, such as environmental factors, the incidence of patent ductus arteriosus is higher in highland areas, which indicates that the highland environment may be one of the pathogenic factors. As mentioned earlier, the causes of congenital heart disease are multiple, so prevention is particularly important, and in the case that most of the causes are still unknown, prevention work should start early and strive to be meticulous. Some experts have pointed out that the main reason for congenital defects is the lack of awareness of self-care, so the prevention of congenital heart disease in children should start before and during pregnancy. Pre-conception health care is very important, and couples who want to have a baby should implement strict preventive measures: a reasonable diet before pregnancy, ban on smoking and alcohol, stay away from toxic and harmful substances, and supplement folic acid in the right amount; women should increase nutrition and strengthen physical exercise before pregnancy to enhance their resistance to disease; those who are exposed to radiation for a long time or receive radiation treatment should get pregnant after six months of being free from radiation; women who are often exposed to various pesticides and chemical drugs should strengthen their protective measures; and those who are not exposed to radiation should not use it. Women should strengthen protective measures; do not use or use less tetracycline, sulfonamide and hormone drugs, do not use cosmetics containing hormones. Conduct maternity checkups on time during pregnancy to make timely diagnosis of whether the fetus is suffering from hereditary diseases and congenital defects. In addition, patients with diabetes and epilepsy are advised to decide whether and when to become pregnant under the guidance of a doctor.