Congenital heart disease is a common pediatric disease with a high incidence. According to foreign literature, its incidence is about 0.4-0.8% of the surviving infants. In China, the incidence of congenital heart disease is 0.6-1.0% according to the survey results, which means that there are about 100,000 or more newborns suffering from congenital heart disease in China every year. The exact cause of congenital heart disease has not yet been determined, but it is mainly a group of congenital malformations of cardiovascular anatomical structure abnormalities caused by malfunction or developmental disorders of the heart and large blood vessels in early embryonic development. It includes dozens of developmental abnormalities of the heart or large blood vessels ranging from simple to complex. The causes of congenital heart disease are broadly divided into two categories: endogenous and exogenous factors. The internal factors are genetic factors, such as chromosomal abnormalities and genetic aberrations, and about 4% to 5% of congenital heart diseases are caused by chromosomal disorders, such as Marfan’s syndrome, heart-hand syndrome and so on. External factors are relatively numerous and complex, among which the more important ones are infections, especially viruses such as rubella virus, mumps virus, influenza virus and coxsackie virus, and some parasites that live in pets. The critical period of heart embryonic development is between the 2nd and 8th week of pregnancy, causing congenital cardiovascular malformations also occur mainly at this stage, such as the mother in the third month of pregnancy with a serious viral infection, especially after the rubella virus, the incidence of congenital heart disease is higher in newborns born. External factors also include intrauterine environment and maternal factors such as local mechanical compression around the fetus, nutritional or vitamin deficiencies of the mother, which can also affect the fetal heart development. Other factors such as highland areas, where the incidence of ductus arteriosus is higher, suggest that the highland environment may be a factor in the development of the disease. Other factors such as maternal exposure to high doses of x-rays or use of certain drugs during pregnancy, chronic diseases, hypoxia, maternal advanced pregnancy, abortion preservation and multiple births are all high-risk factors. For the above mentioned internal and external factors, the prevention of congenital heart disease needs to start before pregnancy. In order to have a healthy body for the newborn baby, the expectant parents should first of all have a more detailed medical examination before preparing for pregnancy, and chromosomal examination should be performed for the high-risk group; secondly, they should quit bad habits: smoking, alcoholism, drug abuse, and treat various diseases as much as possible, and temporarily reduce or avoid contact with pets. The first trimester of pregnancy is a critical period for the formation of the fetal heart, if you are infected with influenza, rubella, mumps and other viruses, exposed to x-rays, isotopes, radioactive elements and other radioactive substances, or taking teratogenic drugs, excessive alcohol consumption or lack of certain nutrients, etc., it may affect the fetal heart development. It may affect the fetal heart development and lead to precocious heart disease. It is also important to avoid contact with pets at this time. There are still many unknown factors in the occurrence of precardiac disease, and it remains for medical workers to continue their efforts.