Congenital cystic dilatation of the bile ducts, also called bile duct cysts, is common in Asian countries (Japan, China) and rare in Western countries. It can occur in any part of the intrahepatic and extrahepatic bile ducts and has multiple manifestations, with a male to female incidence ratio of 1:3 to 4. Its etiology is not well understood, but the possible causes are: congenital biliopancreatic duct coaptation abnormalities, congenital biliary tract developmental abnormalities and genetic factors. The main symptoms are: abdominal pain, right upper abdominal mass, and jaundice. In advanced stages of the disease, biliary cirrhosis and portal hypertension may appear. It mostly develops in childhood, and untreated patients may develop cancer in adulthood. Therefore, once this disease is clearly diagnosed, it should be treated with early surgery, which is mainly cystectomy + bile-intestinal anastomosis.