Choledochal cysts, also called congenital bile duct dilatation, are most common in pediatric patients and commonly present with abdominal pain, jaundice, and abdominal masses, and should be treated surgically once diagnosed. The resection of extrahepatic cyst shows the lower end of the common bile duct, almost reaching the confluence with the pancreatic duct. The dissection of the lower common bile duct requires some skill to ensure that the separation is performed in the correct tissue gap to ensure as little bleeding and damage to the pancreas as possible. Otherwise, there is a risk of damaging the pancreas and pancreatic duct, leading to the formation of postoperative pancreatic leak. The severed end of the posterior hepatic duct is excised, showing the right and left hepatic ducts, and prepared for bile-intestinal anastomosis with the small intestine. After the completion of bile-intestinal anastomosis.