Endoscopic duodenal sphincterotomy (EST) is a new therapeutic function of electronic duodenoscopy (commonly known as “cholelithiasis in the mouth”) and an important part of minimally invasive biliary surgery. Traditionally, the treatment of bile duct stones, septic cholangitis, biliary ascariasis, pancreaticobiliary stenosis, and papillary stenosis has been performed by open surgery. With the emergence of new equipment and technology, the treatment means of biliary diseases have undergone significant changes. Jaundice and pain caused by pancreaticobiliary diseases can be easily solved by simply inserting duodenoscope through the mouth and performing minimally invasive surgery under the mirror without dissection and open surgery, which is less painful and easy to solve pancreaticobiliary problems.