Congenital choledochal cyst: a disease caused by congenital anomalies of pancreaticobiliary syncytial flow. The reflux of pancreatic fluid into the cyst changes the internal environment of the cyst and is the main cause of cystic lesions. Gallstones are often formed in choledochal cysts, secondary cholangitis, pancreatitis, and more likely to develop malignant changes. The diagnosis of congenital choledochal cyst is not difficult and can be confirmed with the help of ultrasound and enhanced CT. Treatment principle of congenital choledochal cyst: complete resection of choledochal cyst and Roux-en-y anastomosis between the hepatic hilar bile duct and the jejunum is the only treatment for congenital choledochal cyst, which is the gold standard operation. The disadvantages of anastomosis between congenital choledochal cysts and the digestive tract alone: About 15-20 years ago, it was customary to perform duodenal anastomosis for choledochal cysts or choledochal cyst-jejunum anastomosis in surgical clinics at that time. On the one hand, the choledochal cyst itself lacks peristalsis and emptying function, the effect of postoperative cyst emptying is poor, and after anastomosis of the cyst and the digestive tract, bile is not always discharged, like infected cholangitis, liver abscess, gallstone formation; on the other hand, the longer the cyst is not resected, the higher the chance of malignant transformation, so it should be hospitalized as early as possible for surgical treatment. The patients with cyst and jejunum anastomosis are now about 30 years old, this part of the patients should go to the hospital general surgery pancreatic surgery review, from the point of view of preventing cysts from becoming cancerous, they should be operated again as early as possible; once malignant and then operated, it is better to be operated at the earliest possible time. Our experience: I have repeatedly performed radical surgery (PD) for adult patients with congenital choledochal cysts, choledochal cysts after jejunoileal anastomosis or choledochal cysts and duodenal anastomosis after malignant lesions, and many cases of choledochal cysts and duodenal anastomosis or jejunal anastomosis were performed in the pediatric population, and malignant lesions occurred at the lower end of the cysts or anastomosis after 15-20 years, or anastomotic choledochal malignant lesions occurred in the elderly after cystectomy. lateral malignancy, etc. The youngest patients were as young as 20 and 27 years old, and many of them had developed lymph node metastasis around the head of the pancreas (intraoperative freezing). A good outcome was obtained after surgery. The malignancy rate of these patients is high, and there is a lack of statistical data in this area in China. We have also seen patients admitted with cholangitis, and after hospitalization, the examination found that the cyst was malignant, combined with liver abscess and multiple metastatic carcinoma of the liver, and the chance of surgical treatment had been lost. Patients with congenital choledochal cysts alone after anastomosis with the digestive tract should come to the hospital for review and consultation with a specialist or a professor, and should opt for reoperation! What surgery should be done for reoperation? In order to prevent malignancy, patients with unresected congenital choledochal cysts should be followed up and reopened. According to the preoperative examination data and intraoperative findings, those who have not yet developed malignancy should have their cysts completely resected and reapply the anastomosis of the hepatic hilar bile duct with the jejunum; those who have already developed malignancy or those who have suspicion of malignancy should be subjected to pancreatic head-duodenectomy, and the resection of the head of pancreas and duodenum should be achieved as R0. Better therapeutic effect can be obtained.