The current cure rate of gastric cancer has been greatly improved compared with before. If gastric cancer is detected early and treated by surgery, the survival rate of 5 years can reach 90%-95%; while the cure rate of first and second stage gastric cancer is 40%-50%. Therefore, to achieve early diagnosis, we should pay attention to the following twelve words: pay attention to abnormal signals, regular gastroscopy and upper gastrointestinal imaging examination. First of all, people should pay attention to some abnormal signals of their body: for example, people who did not have stomach pain before have recurrent stomach pain recently; or although they had stomach pain before, the nature, intensity and regularity of the pain have changed recently; longer-term loss of appetite, upper abdomen fullness and discomfort or hidden pain; unexplained weight loss, unexplained black stool, etc. Meanwhile, it is especially important to note that the peak age of gastric cancer incidence is 40-60 years old, especially for people with tobacco and alcohol habits, unclean diet or chronic gastric diseases (such as chronic atrophic gastritis, gastric ulcer, gastric polyp, residual stomach after major gastric resection surgery, black warty gastritis, etc., which are often called precancerous lesions). People at high risk of stomach cancer should have gastroscopy every 6 to 12 months. Gastroscopy not only can directly see the lesions, but most importantly, it can obtain pathological diagnosis through biopsy. Upper gastrointestinal imaging can detect local mucosal lesions and the extent of lesions.