There are several examination methods to diagnose gallstones. Ultrasound is the first choice for gallstones, and has the advantages of convenience, non-invasiveness, and high diagnostic accuracy. ultrasound is highly accurate for gallbladder stones, with a diagnostic accuracy of over 95%, and can be performed at the bedside for the elderly and critically ill patients, which is convenient. Ultrasound examination is good for acute and chronic cholecystitis, gallbladder stones, and bile duct stones inside and outside the liver. ultrasound is more sensitive than CT in diagnosing gallbladder stones, and has typical signs, so gallstones are usually not selected for CT examination. However, the disadvantage of ultrasound examination: the stones in the lower part of the common bile duct are located behind the duodenum, and ultrasound examination is difficult to show the stones in the lower part of the common bile duct because of the interference of gas in the gastrointestinal lumen. CT examination can clarify the location and cause of gallstones. When there is a high suspicion of common bile duct stones or intrahepatic bile duct stones, or bile duct obstruction within or outside the liver of unknown origin, CT examination is feasible if the diagnosis is not clear by ultrasound examination. MRCP is the best basis that can show the location of gallstones and the degree of dilatation after bile duct obstruction. The value of conventional MRI is limited, but MRCP can replace ERCP in the diagnosis of biliary obstruction, and can clearly show the location of gallstones and the degree of dilatation after bile duct obstruction. ERCP is an invasive test and is mainly used for the diagnosis and treatment of bile duct dilatation and obstruction, etc. The greatest advantage of ERCP is that it can treat the lesions found. The main complications of ERCP operation are bile duct infection and acute pancreatitis, bleeding, intestinal and biliary perforation, etc. PTC is also an invasive test, which can clearly show the intra- and extrahepatic bile duct system by performing intrahepatic bile duct perforation angiography under the guidance of X-ray or B-ultrasound. For patients with intrahepatic bile duct dilatation and deep jaundice, the success of puncture under X-ray or B-ultrasound guidance is higher; if there is no intrahepatic bile duct dilatation puncture is difficult.