Congenital biliary atresia is the most common condition causing obstructive jaundice in newborns. Extrahepatic biliary atresia is common among them. The incidence is higher in females than in males. The etiology of biliary atresia is still unclear, and there are two main theories. (1) Viral infection theory: It is mainly believed that the destruction of liver parenchymal cells and biliary epithelial cells caused by viruses or other causes is a progressive inflammatory process that occurs in the bile ducts before birth and shortly after birth. It is also believed that biliary atresia and neonatal hepatitis are manifestations of different periods of the same disease process, and that hepatitis can spread to the extrahepatic bile ducts and peribiliary tissues with inflammatory changes leading to biliary atresia. In Southeast Asian countries where the incidence of hepatitis B is high, the incidence of biliary atresia is also high. (2) The theory of congenital developmental malformation: In the early embryonic period, the primitive bile ducts are already formed. If the development is impaired at 2-3 months of embryonic age, it may lead to total or partial biliary atresia. Biliary atresia is often combined with malformations such as inferior vena cava agenesis and portal heteroplasia. It is also thought that the condition is associated with chromosomal abnormalities. Surgery is the only effective treatment and should be performed within the first 2 months of life when irreversible liver damage has not yet occurred. If surgery is performed too late and the child has developed biliary cirrhosis, the prognosis is extremely poor.