With advances in endoscopic technology, gastroscopy is not only used for routine diagnosis and detection of ulcers, cancer and other diseases. Now, it is available for electrocoagulation and electrodesiccation therapy, drug injection to stop bleeding, foreign body removal, percutaneous endoscopic gastrostomy, esophageal and pyloric stenosis dilation treatment, etc., enabling patients to avoid surgery and cure some serious gastrointestinal diseases. The most noteworthy endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) in the Department of Gastroenterology of Wuhan Union Medical College Hospital, which can be performed for early gastric cancer, has become one of the minimally invasive surgical methods for early gastric cancer with the features of less damage, mild postoperative pain, quick recovery and discharge. With one-time endoscopic resection of early gastric cancer, the five-year survival rate of patients has reached over 85%. The characteristics of this endoscopic treatment method include: 1. small trauma, rapid recovery of organ function after surgery, mild pain and early departure from bed; 2. surgery under closed conditions, avoiding the influence of exogenous factors of open surgery; 3. video recording is available at the same time of treatment, providing visual image data for postoperative retreatment and academic communication. Disadvantages: Postoperative pathological histological examination requires additional laparoscopic surgery or surgical radical surgery if the residual cancer at the severed end or cancer infiltration depth below the submucosa layer is confirmed in cases. For the adjuvant diagnosis of early gastric cancer, there are also some new means of endoscopic techniques, which are ultrasound gastroscopy and magnified stained gastroscopy. Ultrasound gastroscopy has the dual function of endoscopy and ultrasound examination, which is a targeted ultrasound examination of the suspected lesions in the digestive tract under the surveillance of gastroscopy. Specifically, the ultrasound probe of different frequencies is installed on the front end of the electronic gastroscope, and when the endoscope enters the body cavity, the luminal morphology is directly observed through the endoscope, while real-time ultrasound scanning can be performed to obtain the histological characteristics of the canal wall level and the ultrasound images of the surrounding adjacent organs, so as to further improve the diagnosis and treatment level of endoscopy and ultrasound, which can discover the gastrointestinal, hepatobiliary and pancreatic that cannot be detected by conventional ultrasound and CT It has the advantages of non-invasive, less painful and accurate diagnosis. Ultrasound gastroscopy is especially important for diagnosing early gastric cancer and aiding in the prognosis of gastric cancer. Magnified endoscopy can magnify 70-150 times with high definition, which makes the surface microstructure of the mucosa of the digestive ducts clearer and observes the microvascular pattern of the mucosal surface and the characteristics of the opening of the glandular ducts; special mucosal staining, known as stained gastroscopy, is performed during endoscopy, which can make the boundary between the lesion and the surrounding tissues clear and clearly show the shape, edge and scope of the lesion. Therefore, magnified stained gastroscopy, through its unique principle, helps to detect early gastric cancer for further minimally invasive endoscopic treatment.