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. The following factors may affect fetal development and produce congenital malformations. (1) Environmental factors of fetal development: (1) Infections: 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 coxsackie virus. (2) Other: such as lesions of the amniotic membrane, fetal compression, early gestational pre-eclampsia, maternal malnutrition, diabetes, phenylketonuria, hypercalcemia, the application of radiation and cytotoxic drugs in the early stages of pregnancy, and the mother’s excessive age all 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, may be caused by parental germ cells, 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 sexes, indicating that altitude and sex of birthplace are also related to the occurrence of this disease. In patients with congenital heart disease, it is very rare to find out the definite cause, but it is of positive significance to strengthen the health care of pregnant women, especially to actively prevent rubella, influenza and other rubella viral diseases and avoid some factors related to the onset of the disease in the early stages of pregnancy, to prevent congenital heart disease.