Ultra-fine gastroscopic transoral bile duct exploration was first performed with ERCP, bile duct cannulation was completed, papillary sphincterplasty was performed with CRE dilating balloon, and then the ultra-fine gastroscope (5.9 mm diameter) was replaced to enter the common bile duct, allowing direct visual observation of lesions in the bile duct lumen for targeted biopsy or treatment. The Department of Gastroenterology has completed one case of intrahepatic bile duct adenoma biopsy and one case of bile duct exploration after removal of a metal-clad stent placed for bile duct injury. Ultra-fine gastroscopic transoral bile duct laser lithotripsy starts with placing a laser fiber into the common bile duct through a nasogastroscope, the end of which is in contact with the surface of the stone, and then emitting the laser. Currently, the Department of Gastroenterology has completed 2 cases of ultra-fine gastroscopic endobiliary laser lithotripsy. This new technique is less traumatic than laparoscopic or open surgery for stone extraction, with fewer postoperative complications and faster postoperative recovery, and is a safe and effective endoscopic treatment for difficult-to-take bile duct stones.