A wide range of indications, all suspected esophageal, gastric and duodenal diseases with unclear diagnosis can be examined, specifically: 1, dysphagia, retrosternal pain, burning, epigastric pain, discomfort, fullness, decreased appetite of unknown origin. 2, upper gastrointestinal bleeding. Wang Lirong, Department of Gastroenterology, Nanjing Second Hospital 3.Barium X-ray examination can not confirm the diagnosis, suspected of mucosal lesions or tumors. 4.Lesions that need to be followed up and observed. 5.Observation before and after drug treatment or follow-up after surgery. 6.Patients who need endoscopic treatment (foreign body, bleeding, stenosis expansion, polyp removal, etc.).