Pediatric congenital choledocholithiasis (choledochal cyst) is one of the most common congenital biliary malformations in clinical practice. Its lesion mainly refers to a part of the common bile duct is cystic or spindle-shaped dilatation, sometimes can be accompanied by intrahepatic bile duct dilatation of congenital anomalies. The incidence is higher in females than in males, accounting for about 60% to 80% of the total incidence of pediatric congenital choledocholithiasis (choledochal cyst). This condition is also known as choledochal cyst, congenital choledochal cyst, congenital choledochal dilatation, and primary choledochal dilatation. Etiology: Possible causes include: (1) malformation of the embryonic development of the bile duct. (2) Obstruction of the end of the common bile duct. (3) Poor development of nerves and muscles at the distal end of the common bile duct. (4) Hereditary factors. (5) Abnormal pancreaticobiliary ductal meridian pathogenesis. (6) Combination of multiple factors. Differential diagnosis: 1, cystic type to the right upper abdomen or epigastric mass as the prominent manifestation, without jaundice differential: (1) hepatic encapsulation (2) hepatic cysts (3) retroperitoneal cystic mass (4) nephroblastoma (5) pancreatic cysts pseudopancreatic cysts in children (2) with jaundice as the prominent manifestation of the differential: (1) biliary atresia (2) bile duct orifice pot-bellied periampullary carcinomatosis. It is worth noting that this disease has a high cancer rate of biliary tract cancer, and intermittent abdominal pain and fever are the main complaints in more than half of the cases of biliary tract cancer, which is slightly more frequent than that of this disease without cancer. About 30% present with jaundice and palpable abdominal mass. The presence of back pain and lethargy suggests a progressive stage. It is easily confused with the primary disease because of the lack of specific manifestations of its carcinoma. Therefore, once ultrasound, CT, ERCP imaging, etc. find the shadow of a mass in the dilated bile duct, it should be highly suspected. Analyzing more than 300 cases of carcinoma, the foci were only confined to the muscular layer, and the number of early cases was less than 10, which showed that the diagnosis was extremely difficult. In addition to the diagnosis and basic classification of the disease, the presence or absence of abnormal pancreaticobiliary flow and its morphology, whether there are stones in the common channel, whether there is dilatation of the intrahepatic bile ducts, and whether there is stenosis of the bile ducts in the hepatoportal part of the liver, and other pathologies should be understood before or during the operation, in order to guide the correct treatment. Treatment. Treatment: The principles of treatment for congenital choledocholithiasis can be summarized as follows: (1) Under the premise of meeting the physiological requirements as far as possible, anastomosis between the intestines and the proximal bile ducts should be carried out. The obstruction of the common bile duct is relieved, and bile is restored to the intestinal tract. When reconstructing the bile duct, it is required to ensure that the anastomosis is large enough to avoid twisting and angulation of the anastomosed intestine. (2) Resection of the dilated common bile duct and gallbladder to rule out the possibility of future biliary tract cancer. (3) Perform a pancreatobiliary shunt to address the problem of abnormal pancreaticobiliary coaptation. (4) Understanding and resolving the presence of dilated or narrowed intrahepatic bile ducts and intrahepatic bile duct stones. (5) Understand and address the possible presence of pancreatic stones in the common pancreaticobiliary tract.