Gastroscopy is the preferred method of examination for upper gastrointestinal disorders and has the advantages of safety, non-invasive, clear images and high confirmation rate. Patients with the following symptoms need gastroscopy: foreign body sensation in the throat, difficulty or pain in swallowing, heartburn and acid reflux, pain and burning sensation behind the sternum, upper abdominal pain, fullness, loss of appetite, weight loss and other symptoms of unknown origin; upper gastrointestinal bleeding of unknown origin; lesions requiring follow-up observation, such as ulcer disease, atrophic gastritis, post-surgical residual stomach, reflux esophagitis, Barrett’s esophagus, etc.; drug treatment Patients who need endoscopic treatment, such as foreign body removal, hemostasis, stricture dilation, stent placement, polyp removal, precancerous lesions and early cancer resection, etc.