ERCP (Endoscopic Retrograde Cholangio-Pancreatography, ERCP): Transendoscopic retrograde cholangiopancreatography is an imaging technique that applies electronic duodenoscope and related instruments to insert and inject contrast agent through the mouth to the duodenal papilla, thus retrograde display of the pancreaticobiliary duct, which is currently recognized as the gold standard for the diagnosis of pancreaticobiliary duct diseases. On the basis of ERCP, interventions such as duodenal papillary sphincterotomy (EST), stone extraction, endoscopic nasal bile drainage (ENBD) and biliary stent placement (ERBD) can be performed, which are now widely used for the minimally invasive endoscopic treatment of biliary stones and biliopancreatic tumors. The advantages of ERCP are: no need to open to, minimally invasive surgery, small trauma, fast recovery, and does not change the original anatomy of the body, does not affect the subsequent treatment; hospitalization time; for patients who do not exist surgical open surgery conditions, especially the elderly more advantageous.