Extrahepatic bile duct stones refer to the bile ducts below the primary bile duct, mainly including the hilar bile duct, common hepatic duct, common bile duct, jugular abdomen, and cystic duct. According to the location of the stones, they can be divided into common hepatic duct stones, common bile duct stones, jugular abdominal stones, Mirrizi syndrome, etc. They account for 15.3% to 31.7% of the total gallstone cases. Since 1998, scholars in China have proposed the combination of laparoscopy, duodenoscopy and choledochoscopy (tri-scope) to be flexibly applied in the treatment of bile duct stones, giving full play to the advantages of combined soft and hard scopes, and gradually formed the theory of tri-scope combined stepwise treatment of bile duct stones [3], after more than ten years of experience summing up and development, the “tri-scope After more than 10 years of experience and development, the “three-scope” concept has become a powerful weapon for minimally invasive treatment of extrahepatic bile duct stones. Three-scope stepwise protocol Before performing three-scope treatment alone and in combination, ultrasound, CT and MRCP of the hepatobiliary system should be checked to clarify the location and size of the stone, the diameter of the bile duct, the presence of stenosis, variation, and the relationship between the stone and the bile duct, etc., and to assess the general condition of the patient and whether he can tolerate the operation. If one part of the treatment process fails, the patient can flexibly switch to another plan. Endoscopic sphincterotomy (EST) is suitable for simple choledocholithiasis without gallbladder stones or resected gallbladder, especially for choledocholithiasis combined with lower choledochal stenosis, advanced age, multiple organ insufficiency, high surgical risk, previous history of biliary surgery. The procedure is particularly suitable for patients with common bile duct stones combined with lower bile duct stenosis, advanced age, multiple organ insufficiency, high surgical risk, and previous biliary history. Patients with acute biliary pancreatitis and acute severe cholangitis caused by choledocholithiasis should first undergo emergency EST+ENBD, with the exception of embedded stones in the biliopancreatic jugular abdomen, which should not be retrieved for the time being to maintain patency and drainage, and then be treated with lithotripsy at a later stage after pancreatitis and biliary tract infection are effectively controlled. However, it is worth noting that EST has its own contraindications, which are summarized as follows: (l) the presence of lesions upstream of the papillary sphincter that cannot be resolved by EST, such as: intrahepatic bile duct stones, bile duct stones with a large diameter (diameter of more than 2 cm) and hard texture (difficult to crush in the mesh basket), Mirizzi syndrome, bile duct stenosis in the lower part of the bile duct and above the papilla, etc.; (2) very poor general condition of the body, heart, brain, liver (2) Very poor general condition of the body, heart, brain, liver, etc. (3) Patients with severe coagulation disorders and bleeding disorders, such as acute cholangitis of severe type (ACST), coagulation abnormalities due to acute liver damage, and severe thrombocytopenia due to severe infection (PLT <2ox109/L is an absolute contraindication). (4) Low-age patients, there is a trend of clinical reports of younger age of EST cases, even children, due to the existence of long-term complications of EST and the longer life expectancy of young people, so young patients should be used with caution. Complications EST and LCBDE (T-tube placement and one-stage suturing) have their own characteristics and have their own complications, which can be divided into immediate and long-term complications according to the time of complications. ERCP+EST+ lithotripsy has the unique advantages of minimally invasive, less invasive and faster postoperative recovery, especially for the elderly with contraindications to surgery, however, its technique is slow to master and has a long learning curve.