Tumorous polyp is a true tumor of the epithelial cell proliferation of the large intestinal membrane, and its single occurrence is collectively called adenoma, which can be divided into three categories: adenoidal, villous and mixed, depending on its histological features and biological behavior. Other adenomas include non-familial adenomatosis, Gardner’s syndrome and Turcot’s syndrome, which have different malignant rates and are considered precancerous, therefore, early diagnosis and treatment of adenomas are of great importance. The treatment of gastric and intestinal polyps and early cancerous lesions used to be mainly surgical, but it is very traumatic and the recovery of patients is slow, and the removal of diseased organs often causes different degrees of functional disorders. With the improvement of gastroscopy technology, minimally invasive gastrointestinal surgery has developed rapidly, and the concept of gastrointestinal polyp and early tumor treatment has been revolutionized. Endoscopic submucosal dissection (ESD) is the result of this revolution, which refers to the endoscopic use of high-frequency electric knife and special instruments to gradually peel off the gastrointestinal lesions (including early gastrointestinal tumors) from the normal submucosal layer beneath them to achieve the purpose of complete removal of the lesions at the maximum extent and depth. It has become one of the major minimally invasive procedures for the treatment of early cancer and precancerous lesions in the gastrointestinal tract. ESD has the same purpose and similar practice as mucosal resection, but has the advantages of complete resection of larger lesions larger than 2 cm and lower recurrence rate. ESD can completely resect larger lesions at one time to avoid tumor residue and recurrence, and compared with traditional gastrectomy or radical resection of early gastrointestinal cancer, ESD has less damage, lower cost and faster postoperative recovery. Like other endoscopic treatments, ESD also has certain risks. The main complications are bleeding and perforation, with an incidence of about 5-8%. A small number of patients require surgical treatment. Even so, ESD is a simple, effective, and less invasive method of treating gastrointestinal lesions with efficacy comparable to that of surgery.