Recently, a patient with a large submucosal bulge in the esophagus was admitted to our gastroenterology department. The patient’s external gastroscopy revealed a submucosal bulge of 2.0*1.5 cm in size in the esophagus 26 cm from the incisors, and ultrasound endoscopy (EUS) suggested an origin in the lamina propria. As a rule, endoscopic submucosal resection (ESD) could be performed to excise the lesion, but the lesion was huge and deeply located, which was highly susceptible to perforation, and endoscopic closure after perforation was difficult. In addition, the location is adjacent to the heart, large blood vessels and other important organs, and the consequences of perforation are unthinkable. Facing this great challenge, Prof. Wan Rong of the Department of Gastroenterology decided to use transoral endoscopic submucosal tunnel tumor resection (STER), which is based on another new technique, transoral endoscopic sphincterotomy (POEM), in which a submucosal tunnel is established 3-5 cm away from the side of the tumor, the peritoneum is gradually revealed, the tumor is peeled off under direct endoscopic view, and after complete peeling, the tumor is removed and closed with a metal clip. After complete dissection, the tumor is removed and the tunnel opening is closed with a metal clip. This method can completely dissect most of the submucosal tumors originating from the intrinsic muscular layer at one time, while maintaining the integrity of the GI mucosa, and even if perforation occurs, the tunnel can be closed very quickly and easily, effectively preventing gas and digestive fluid leakage. Compared with the previous resection method ESD, this procedure not only avoids the recurrence of postoperative GI fistula and thoracoabdominal infection, but also has a smaller surgical incision, faster recovery, shorter hospital stay and reduced medical costs, fully demonstrating the superiority of minimally invasive surgery. After thorough preoperative preparation, Prof. Wan successfully completed the surgery, and the patient recovered well after the operation without complications such as bleeding and perforation, and was able to eat and drink normally soon afterwards. As one of the most cutting-edge technologies in the field of gastrointestinal endoscopy in the world, the successful implementation of POEM and STER procedures in our gastroenterology department shows that the development level of our gastrointestinal endoscopy center has been in line with international standards.