In many cases, when patients present to the hospital with symptoms of distension and pain in the upper abdomen and other discomforts, gastroenterologists often recommend that patients undergo gastroscopy because it is very versatile. From the diagnostic aspect, it provides a good observation and understanding of papillary lesions in the esophagus, cardia, stomach, duodenum bulb, descending, and the opening of the common bile duct. It can not only directly observe the site, extent and degree of lesions, but also magnify the lesions tens or even hundreds of times to carefully observe the opening morphology of the glands to help determine the disease status, or to perform staining observations to provide clinicians with informative and reliable information. If necessary, biopsies of suspicious lesions are extracted and then examined pathologically to clarify the nature of the lesion. For example, to determine the degree of chronic gastritis and the presence of intestinal epithelial metaplasia, to identify benign and malignant ulcerative lesions, and to detect gastric cancer at an early stage. Therefore, with the help of gastroscopy, the doctor’s diagnosis of chronic gastritis and peptic ulcer can be elevated from morphological understanding to cytological understanding. In this way, the diagnosis of the disease is more precise and more instructive for treatment and prognosis judgment. Also gastroscopy can be photographed and videoed for clinical research, teaching, scientific research and post-treatment comparison applications. Gastroscopy is not only used for the diagnosis of upper gastrointestinal tract diseases, another important feature of gastroscopy is that it can carry out various gastroscopic treatments.