The timing of gastroscopy depends on different groups of people and different gastric diseases. For people without underlying gastric disease, if they have no clinical symptoms and are under 45 years of age, it is recommended to perfect gastroscopy when they have symptoms. If you are older than 45 years old, especially if you have chronic atrophic gastritis, peptic ulcer (especially gastric ulcer) or reflux esophagitis, family history of gastric cancer and other gastrointestinal diseases, you should review gastroscopy regularly. The frequency of review depends on the disease condition and family history of gastric cancer, and it is generally recommended to review gastroscopy once a year. In the case of chronic atrophic gastritis, different review times are clinically determined according to whether the intestinal epithelial hyperplasia is mild, moderate or severe; moderate to severe intestinal epithelial hyperplasia is generally recommended to review gastroscopy once every six months, and mild is recommended to review gastroscopy once every 1-2 years. For older patients with common non-atrophic gastritis with H. pylori infection, it is generally recommended to review the gastroscopy once every 1-2 years. Before doing gastroscopy, we should pay attention to fasting for 6-8 hours, fasting examination to avoid food affecting observation, to prevent vomiting and choking during the operation, and if there are active dentures, to remove them in advance.