Gastric cancer is one of the most common malignant tumors that threaten human life, and its incidence rate increases significantly with age. Gastric cancer in China is characterized by “three highs” and “three lows”, including high incidence rate, high mortality rate, high metastasis rate, low early diagnosis rate, low resection rate and low 5-year survival rate, which brings heavy burden to patients and their families. Early gastric cancer mainly has the following signals: First, stomach pain. Initially, it only feels discomfort in upper abdomen or bloating, and sometimes vague pain in the heart, which is often mistaken for the pain of gastritis or ulcer disease. Secondly, loss of appetite, emaciation and weakness. It is often the first symptom of stomach cancer, accounting for about 40%. The third is nausea and vomiting. In the early stage, there may be only a feeling of fullness and nausea, which is mainly caused by gastrointestinal dysfunction caused by tumor. Fourth is bleeding and black stool. Fifthly, there is pressure pain in the upper abdomen. Since the early symptoms of gastric cancer are insidious and often similar to gastritis and peptic ulcer, more than 70% of gastric cancer patients are already in the middle or late stage when diagnosed. Older people are often less sensitive to early symptoms, and they are often diagnosed late, and the symptoms of tumors are often hidden due to the combination of chronic diseases of heart, brain and lung, so that timely examination is missed. Experts suggest that middle-aged and elderly people should pay attention to the precursors of stomach cancer in their life. If there is no history of stomach disease but the symptoms of suspected early stomach cancer appear in the near future, they should not be easily considered as general stomach disease, but should pay high attention to it and seek medical treatment early to receive gastroscopy and other examinations in order to detect stomach cancer at an early stage, and once it is diagnosed, they should go to regular hospitals to receive standardized treatment in order to get better treatment results. To achieve early detection of gastric cancer, one is the screening of healthy people; the other is to rely on people’s alertness to gastric cancer and their awareness of early symptoms. For high-risk groups of gastric cancer, such as chronic atrophic gastritis, gastric ulcer, gastric polyp and pernicious anemia, after most of gastric resection; family history of gastric cancer and other high-risk groups, regular examination should be done for early detection. Fiberglass gastroscopy is the most important method for early diagnosis of gastric cancer. At present, fiberoptic gastroscopy equipment is advanced, and under the operation of experienced and skilled endoscopists, lesions as small as a grain of rice can be detected, and a small amount of tissue can be taken for pathological examination, and most of them can be correctly diagnosed. Once the diagnosis of gastric cancer is confirmed, it should be treated as early as possible and comprehensive treatment measures can be taken, such as radical gastric cancer surgery with preoperative and postoperative chemotherapy, immunotherapy, traditional Chinese medicine and psychotherapy. As long as early gastric cancer is treated timely, the 5-year survival rate can reach 80%-90%. The occurrence of gastric cancer is the result of the long-term combined effect of many factors and is closely related to people’s bad life behaviors and habits. For example, salt-cured, smoked, fried and baked food; strong carcinogenic substances such as 3,4-benzopyrene; deteriorated and moldy food can produce aflatoxin, etc. all have strong carcinogenic effects. Vegetables left for too long will produce nitrite under the action of bacteria, which can be transformed into nitrosamines, a strong carcinogenic substance, and is the culprit of stomach cancer. Other eating behaviors, such as excessive alcohol consumption, salty and hot food, fast eating, lumping and swallowing dates, irregular meals and hunger and satiety, can damage the gastric mucosa and increase the risk of gastric cancer. Severe sleep deprivation, irregular diet, psychological tension and mental stress are important reasons for the increasing incidence of gastric cancer in young people. Preventive measures include: changing the diet structure and bad eating habits; paying attention to a balanced and reasonable diet; drinking less strong alcohol and not smoking; being cheerful and optimistic; choosing food additives, coloring agents and spices that are harmless to people; eating more foods rich in vitamins, trace elements, protein and fiber; and eating less greasy, animal fat and sweet food.