Gastroscopy is a commonly used test for diagnosing gastrointestinal diseases. With the development of technology in recent years, many gastrointestinal tumors can also be treated under gastroscopy, so that patients can avoid surgery and reduce pain. Commonly used treatment methods include: endoscopic resection for early gastric cancer: transendoscopic mucosal resection (EMR) is an endoscopic treatment technique developed in recent years. Its indications mainly include: 1. Resection of precancerous lesions, such as severe atypical hyperplasia foci, flat bulging adenoma, etc. 2. 2.Certain lesions for which conventional gastroscopic biopsy is not enough to make a diagnosis, such as the depth of infiltration of early gastric cancer, antiphlogistic lymphoid hyperplasia, submucosal tumors and so on. 3.For early gastric cancer, in the absence of ulcer or ulcer scar, and without vascular invasion or lymph node metastasis. Figure 1: Injection and circling cutting method: inject the solution at the base of the tumor to make the tumor bulge, and then circling cutting Figure 2: Injection, grasping and circling cutting method: during the operation, retract the clamping forceps before the circler is placed at the base of the lesion and tightened Figure 3: After the submucosal injection, the transparent cap is aligned to the lesion with continuous suction, and after the lesion is sucked into the cap, the circler is put over the lesion and tightened, the suction is stopped, and the lesion is withdrawn from the transparent Figure 4: This method eliminates the need for submucosal injection.