The etiology of precocious heart disease is complex and remains a worldwide problem. Comprehensive domestic and international research results show that the causes of congenital heart disease can be broadly divided into three aspects: genetic factors, environmental factors and disease drug factors, as follows: 1. Genetic factors Genetic factors include single gene, multiple genes, chromosomal abnormalities related diseases, etc.. In trisomy 21, for example, about 50% of patients have congenital heart disease, of which endocardial cushion defect and ventricular septal defect account for 32% and 29% respectively, followed by atrial septal defect accounting for 11%, tetralogy of Fallot accounting for 7.9%, and end ductus arteriosus accounting for 6.7%. Most of the simple atrial septal defects, ventricular septal defects, patent ductus arteriosus, and tetralogy of Fallot show polygenic pattern, and the risk of reoccurrence of their siblings and children is around 4%. 2, environmental factors refers to the environment in which the pregnant woman is exposed to before and during pregnancy, including the living and working environment, including chemical and physical factors. Chemical factors are mainly long-term exposure to harmful chemicals, including benzene, sulfur dioxide and other harmful gases and heavy metals such as mercury and cadmium. Therefore, pregnant women should avoid living in newly renovated houses, as well as avoiding exposure to chemical factors and strengthening protection. Physical factors are mainly radiation, because radiation has a pathogenic effect on the human body and a teratogenic effect on the fetus. 3.Disease and drug factors Drug and disease factors mainly include alcoholism of mother, aspirin of mother in early pregnancy, taking tetracycline, taking contraceptive pills, rubella and cold. These are all high-risk factors that lead to congenital heart disease in children. Therefore, mothers should try to avoid drugs and disable high-risk drugs during pregnancy, especially in early pregnancy. In addition, mothers should also avoid colds and bacterial and viral infections such as rubella and measles during early pregnancy, as bacterial and viral infections can also lead to malformations in fetal development and cause congenital heart disease. In addition, advanced maternal age is also a high risk factor for the development of congenital heart disease in the fetus. Experts suggest that for genetic factors, parents who have a family history of genetic diseases should try to rule out the possibility of congenital heart disease in their fetus through chromosome examination and genetic examination during pregnancy; in addition, to prevent the occurrence of congenital heart disease pregnant women should avoid living in newly renovated houses, avoid exposure to chemical factors; avoid exposure to radioactive substances and avoid living in an environment with strong electromagnetic waves; Try to avoid the use of drugs, disable high-risk drugs.