Gastric cancer is a multi-morbidity and common disease, and it is also a rather complex and difficult to treat disease. More than 70% of first diagnosed gastric cancer patients in China are already in the middle and late stages. The length of survival of gastric cancer is closely related to the stage of gastric cancer. The 5-year survival rate of early gastric cancer is 95%, and the 5-year survival rate is less than 20%. The high incidence of gastric cancer is related to many factors such as diet, genetics, mental and environmental factors: experts have done many studies on the causes of high incidence, but so far they have not been able to find the exact causes, the causes of gastric cancer are complicated, so far we can only say that some causes are important factors, such as Helicobacter pylori infection, bad dietary habits, which have a lot to do with our dietary habits. For example, people who consume smoked meat and pickled food (containing nitrosamines) for a long time are also a high-risk group for stomach cancer. Stomach cancer incidence worldwide is mainly concentrated in three countries — China, Korea and Japan, which together account for two-thirds of the world, while the absolute and relative numbers of incidence in China are relatively high, and are dominated by middle and late stage stomach cancer. The detection rate of early gastric cancer in China is 5%-10%, while that of Japan is as high as 80% and that of Korea is 40%. The incidence rate of gastric cancer in China accounts for about 42% of the world, with 400,000 cases per year; the number of deaths is more than two-thirds, so the number of deaths due to gastric cancer is about 300,000 per year, and a large part of the high mortality rate is due to late detection. Compared with Japan and Korea, our gap is ultimately in census. Early gastric cancer can be detected without any symptoms, and it is difficult to be detected by CT, blood sampling or other means, and currently gastroscopy is the best way to detect gastric cancer at an early stage. The best way to detect gastric cancer in early stage is gastroscopy and a pathological section at the same time, which can determine whether your gastric mucosal cells are far away from cancer, or not too far away, or very close to it, because gastric cancer cannot grow out in a day or two days, or a month or two months, there is a process, which usually takes several years. Before the cells of the stomach develop into cancer cells, there are signs: for example, you may have heard of medical terms such as “atrophic gastritis” and “intestinal epithelial metaplasia”. There is medical evidence that chronic atrophic gastritis and intestinal epithelial hyperplasia are precancerous lesions of gastric cancer. Atrophic gastritis and intestinal epithelial hyperplasia can easily develop into gastric cancer, so people with these two diseases found during physical examination should be especially careful. It is recommended that these people should have a gastroscopy every one to two years to keep track of changes in their condition and take effective measures. To see if the “atrophy” is going in a bad direction, or if it is still stagnant and remains the same. Some cells can even regress, from abnormal back to normal cells. Of course, this “see” can not be seen by themselves, but also must be examined with the help of gastroscopy, all we need to do is to raise awareness of active examination. Only through the examination can we know whether the distance between normal stomach and stomach cancer is very far or very close. Otherwise, it is not accurate to say “I don’t feel well”, “I feel something” or “I don’t feel anything”. If the causes of gastric cancer can be blocked in time, the occurrence of gastric cancer will be reduced or eliminated. In the prevention of gastric cancer, tertiary prevention can significantly increase the 5-year survival rate of gastric cancer. Strengthen the popular science education on stomach cancer prevention, correct bad habits, especially bad eating habits, do not eat hot food, do not eat too fast, do not eat too salty food, avoid mechanical damage to the upper digestive mucosa; eat less or no salt-pickled food, no moldy food, less smoked, fried and baked food, reduce the intake of carcinogens; maintain an optimistic and cheerful mood, do not eat in anger, do not smoke, keep the body immune and nervous system in good condition. keep the immune and nervous system in good condition. Promote eating more fresh vegetables and fruits. Early detection, early diagnosis and early treatment: If one of the relatives in two or three generations has had digestive system tumor or other tumors, the chance of getting stomach cancer is higher. The response is to do professional tumor screening about 10 years earlier than the minimum age of cancer members in the family. Gastroscopy should be done for gastric cancer, every 3 years, and the specific targeted examination can be individualized according to the doctor’s suggestion. Surveillance for high-risk groups of gastric cancer: patients such as chronic atrophic gastritis, intestinal epithelial hyperplasia, gastric ulcer, gastric polyp, postoperative residual stomach, pernicious anemia and various gastric diseases due to HP positivity, especially patients with family history of gastric cancer and patients over 40 years old with gastric diseases that have not been cured for a long time, should be reviewed regularly. Currently, the recognized method for early diagnosis and early detection of gastric cancer is gastroscopy, which can not only help doctors discover small lesions in the stomach, but also provide timely treatment through minimally invasive surgery. Doctors suggest that people with high risk of gastric cancer should have at least one gastric endoscopy to prevent the disease before it happens; gastric cancer is the most common digestive system tumor, so the general public should also have a gastroscopy checkup over 45 years old.