The exact cause of congenital heart disease is still unclear, and research has concluded that it is the result of the interaction of genetic and environmental factors, and the following factors may affect the development of the fetus and produce congenital malformations. 1, the environmental factors of fetal development: (1) infection: the incidence of congenital heart disease is higher in babies born with viral or bacterial infections in the first trimester of pregnancy, especially rubella virus, followed by coxsackievirus. (2) Other: such as amniotic membrane lesions, fetal pressure, early pregnancy pre-eclampsia, maternal malnutrition, diabetes, phenylketonuria, hypercalcemia, the application of radiation and cytotoxic drugs in the early stages of pregnancy, the mother is too old, etc. have the potential to cause congenital heart disease in the fetus. 2, genetic factors: congenital heart disease has a certain degree of family tendency to develop, which may be caused by parental germ cells and chromosomal aberrations. Genetic studies have concluded that most congenital heart disease is formed by the interaction of multiple genes and environmental factors. 3.Other: Some congenital heart diseases are more frequent in highland areas, and some congenital heart diseases have significant differences in incidence between male and female gender, indicating that altitude and gender of birthplace are also related to the occurrence of this disease. Among patients with congenital heart disease, those who can find a clear cause are very few, but strengthening the health care of pregnant women, especially in the early stages of pregnancy to actively prevent rubella, influenza and other rubella viral diseases and avoid some factors related to the onset of the disease, is of positive significance in the prevention of congenital heart disease.