The invention and clinical application of gastrointestinal endoscopy is a major breakthrough in the recent history of gastroenterology. After more than a century of development, gastrointestinal endoscopy has undergone four generations of changes: rigid endoscopy, semi-flexible endoscopy, fiber endoscopy (soft endoscopy) and electronic endoscopy and ultrasound endoscopy, and has entered the advanced stage of minimally invasive interventional technology integrating diagnosis and treatment from the initial stage of pure diagnosis, and various new electronic endoscopes with different functions of upper gastrointestinal tract, lower gastrointestinal tract, biliary tract, magnification, ultrasound and capsule endoscopy. have significantly improved the diagnosis and treatment of gastrointestinal diseases. Staining endoscopy, also known as pigmented endoscopy, applies dye to stain the mucosa of the gastrointestinal tract to enhance the contrast between the lesion and the surrounding normal mucosa, which can reveal lesions that are difficult to detect with the naked eye and help to detect, diagnose and guide biopsy of lesions. After years of development and improvement, this technique has become increasingly mature and is widely used to diagnose gastrointestinal mucosal lesions, especially in the diagnosis of early gastric and esophageal cancers and precancerous lesions, which has shown high value. In China, Wang Guoqing et al. performed endoscopic screening by iodine staining in 3022 cases of people aged 40-69 years old in areas with high incidence of esophageal cancer, and found 827 cases of moderate and severe heterogeneous hyperplasia and superficial esophageal cancer, among which 559 cases were found after iodine staining. Electronic staining technique (representative: NBI) The representative electronic staining technique is narrow-band filter imaging, or NBI, which is based on pigment staining by applying optical imaging techniques such as special filters to narrow the spectrum of the components of white light, while making blue light of short wavelength the relatively major component, mainly by observing superficial blood vessels on the mucosal surface and the fine shape of glandular ducts. It can replace staining endoscopy to a certain extent by reducing the patient’s pain and improving the efficiency of the work. With the widespread use of magnification endoscopy in clinical practice, the combined use of magnification endoscopy for NBI can provide a clearer view of the morphology of mucosal glandular duct openings and microvascular morphology such as the diameter, direction, and presence of branches and spiral changes of microvessels, which can provide more reliable diagnostic information for endoscopists. The magnifying endoscope, also known as microscopic endoscope, can magnify the object under the endoscope 80 times-150 times and can observe the fine structure of gastric mucosal surface and microvasculature around 8µm. Through the magnifying endoscope combined with staining technology can significantly improve the observation and judgment of micro lesions and micro structures, so as to identify normal epithelium, hyperplastic epithelium, heterogeneous epithelium and epithelial tumor, for benign and malignant polyps, The diagnosis of benign and malignant polyps, early carcinoma and atrophic lesions can be made in time, and the depth and extent of tumor infiltration can be judged to provide objective basis for correct selection of endoscopic mucosal resection or surgical treatment. Ultrasonic endoscopy In order to make up for the blind spot in body surface detection and some limitations of endoscopy, the combined device of endoscopy and ultrasound detector? Ultrasound endoscopy (EUS) began to take the historical stage in 1980, more than 20 years of development has made it a more mature endoscopic diagnostic technology. So far ultrasound gastroscopy, ultrasound enteroscopy, ultrasound duodenoscopy and laparoscopic ultrasound system have been successfully used in clinical practice, becoming an important imaging test for the diagnosis and preoperative TNM staging of gastrointestinal malignancies, diagnosis and differential diagnosis of submucosal tumors and further diagnosis of biliary and pancreatic diseases. V. Confocal endoscopy is a new technology that integrates micro confocal microscope in the front end of traditional endoscopy. Its inherent feature of 1000 times magnification enables real-time histological examination of GI mucosal lesions at the same time as endoscopy, which can observe the range of epithelial cells, extracellular matrix and basement membrane, colonic crypt structure, blood vessels and red blood cells, etc. It can replace biopsy and in vitro staining of traditional pathology in many aspects. It can replace biopsy and in vitro staining of traditional pathological examination in many aspects, can guide biopsy, avoid blind biopsy and leakage of suspicious lesions, and has a broad development prospect. Sixth, balloon small intestine microscopy At present, there are two kinds of double balloon small intestine microscopy and single balloon small intestine microscopy, which can observe the whole small intestine directly, and at the same time, biopsy, mucosal staining, marking the lesion site, submucosal injection, polypectomy and other treatment, which is the most promising technology for the diagnosis and treatment of small intestine diseases, and the rate of confirming the cause of unexplained gastrointestinal bleeding reaches 80%. In addition, with the continuous improvement and popularization of laparoscopic examination technology in recent years, the combination of hard and soft microscopy is likely to become an important development direction for the diagnosis and treatment of small bowel diseases in the future. VII. Capsule endoscopy The first capsule endoscope was developed in Israel in 2000, which opened up a new idea for endoscopy. The diagnosis rate of unexplained gastrointestinal bleeding is 81%, which makes a significant progress in the diagnosis of small intestinal diseases, but it is not suitable for those with relatively large amount of bleeding or with intestinal obstruction. At present, capsule endoscopy can only be used for examination, but with the progress of science, robot-like “endoscopes” can not only diagnose but also “repair and treat” intestinal lesions. In conclusion, the ultimate development direction of gastrointestinal endoscopy is to improve the accuracy of diagnosis and the effectiveness of treatment. Since the incidence of gastrointestinal tumors is increasing year by year, the diagnosis and treatment concept of “early diagnosis and early treatment” makes gastrointestinal endoscopy take up the important task of early detection and treatment of gastrointestinal tumors. The common features of these new endoscopic technologies are that they can display special microstructures that cannot be shown by ordinary endoscopy, allow virtual histological examination during endoscopy, and even perform functional diagnosis at the cellular-molecular level to reveal the pathophysiological mechanisms of diseases, reflecting the trend of endoscopic diagnosis toward microscopic development. The use of these new advanced endoscopic techniques in clinical practice will significantly improve the detection rate of early cancerous and precancerous lesions (especially microscopic non-polypoid lesions) in the gastrointestinal tract, and will help in the accurate endoscopic staging and selection of treatment options for these lesions. The use of small bowel microscopy and capsule endoscopy has eliminated the last blind spot in the gastrointestinal examination. The development of science and technology and the innovation of treatment concept will inevitably promote the treatment platform of gastrointestinal endoscopy, the improvement of endoscopic instruments and technology and the perfection of disciplinary theory, and the treatment scope of gastrointestinal endoscopy will become more and more extensive and useful.