Bile duct stones are stones that form in the bile ducts inside and outside the liver and are the most common biliary system disorder. Stone obstruction of the bile ducts causes bile stagnation and secondary bacterial infection leading to the occurrence of acute cholangitis. Repeated inflammation of the bile ducts can cause local wall thickening or scarring stenosis, and bile duct inflammation and stenosis can promote stone formation. The proximal end of the bile duct stenosis is passively dilated and the internal pressure is increased. Clinically, patients often present with right upper abdominal colic, chills and fever, jaundice and other symptoms. Primary bile duct stones are stones formed in the bile duct, mainly bile pigment stones or mixed stones. Secondary bile duct stones are stones from the gallbladder draining into the common bile duct and are mainly cholesterol stones. According to the location of the stones, they are divided into extrahepatic bile duct stones and intrahepatic bile duct stones. Extrahepatic bile duct stones are mostly located in the lower end of the common bile duct; intrahepatic bile duct stones can be widely distributed in both lobes of the intrahepatic bile duct or confined to a particular lobe, with the left outer lobe and right posterior lobe being the most common. Choledocholithiasis: It accounts for more than 50% of acute pancreatitis, mostly caused by the lower end of the common bile duct due to the compression of stones, which can lead to pancreatic duct obstruction. 2. Acute cholangitis: bile duct obstruction caused by bile duct stones, bile duct tissue congestion, edema, and increased pressure in the bile duct, resulting in bile duct infection. 3. Abdominal pain: occurs in the subxiphoid process and the right upper abdomen, mostly colic, paroxysmal attacks, or persistent pain paroxysms, which may radiate to the right shoulder with nausea and vomiting. 4. Chills and high fever: mostly caused by biliary tract infection, bacteria and toxins enter the hepatic sinusoids to the hepatic vein through the capillary bile ducts, and then enter the body circulation and cause systemic infection. High body temperature can reach 39~40℃. 5. Jaundice: Jaundice can occur after bile duct obstruction, and its severity, occurrence and duration depend on the degree of bile duct obstruction, whether it is complicated by infection, the presence or absence of the gallbladder and other factors. Jaundice is often accompanied by darkening of the urine and lightening of the stool, and in some cases, itching of the skin may occur. Third, how to diagnose Generally, ultrasound, CT or MRCP are preferred. How to treat Minimally invasive treatment under duodenoscopy is preferred. In the past, bile duct stones had to be treated by surgical open surgery. However, with the development of gastrointestinal endoscopy, endoscopic retrograde cholangiopancreatography (ERCP) has gradually replaced surgery as the treatment of choice for bile duct stones. Compared with surgical procedures, ERCP has the advantages of no incision, minimally invasive, clean stone extraction, short hospital stay and less pain for patients.