Choledochal cystectomy can stop the reflux of intestinal and pancreatic fluid and prevent the cyst from becoming cancerous. A reasonable procedure to cure the cyst should be cystectomy. Cystectomy used to be considered a difficult and dangerous operation, and operators often abandoned cystectomy and rashly performed internal drainage because of the huge cyst, the difficulty of handling the lower end or the history of multiple biliary tract operations and severe local inflammatory adhesions. The main points of surgical treatment for congenital common bile duct cyst: 1. Preoperative ERCP or MRI examination, intraoperative cystogram and amylase (AMS) measurement of cyst fluid if necessary, to understand whether there is also intrahepatic bile duct cyst, lower biliopancreatic duct confluence and determine whether there is pancreatic reflux. 2. 2. When stripping the common bile duct, the vessels should be avoided, starting from easier places first, and really separating to the vicinity of the portal vein, where the tissues are relatively loose and the anatomical relationships are clear, and usually no blood vessels will be accidentally injured. The cyst should be stripped and transected, and then just like stripping the hernia sac, the cyst should be dissected and freed towards the porta hepatis and distal end respectively, and the cyst wall should be removed as clean as possible to prevent cancer. Intracapsular resection, that is, if it is difficult to peel the cyst, in order to prevent damage to portal vein and hepatic artery, only the inner membrane can be peeled off when removing the posterior wall; or saline can be injected first between the inner and outer layers to make the peeling more convenient. 3. Treatment of distal stenosis: for long stenosis, it is enough to transect it. If the stenosis is short, there is a possibility of damaging the pancreatic duct, so the cyst can be cut open first and a probe can be inserted to help orientation. After cyst removal, the biliopancreatic fluid has been shunted and the cause of chronic irritation of the bile duct no longer exists, so the chance of malignancy of the residual cyst wall can be greatly reduced.