Primary prevention is to study the etiology and risk factors of gastric cancer, and take preventive measures to reduce or eliminate the carcinogenic effects of various carcinogenic factors on human body to reduce the incidence rate by targeting specific carcinogenic and cancer-promoting factors such as chemical, physical and biological factors as well as internal and external pathogenic conditions. Pay attention to diet and water hygiene, do not eat moldy and rotten food, burnt food, smoked, baked, pickled and soaked food, or do not drink water that has been stored for a long time, do not smoke, do not drink alcohol, eat scientifically, eat more fresh vegetables and fruits, and develop good eating habits. At the same time, paying attention to the protection of the environment, avoiding and reducing the pollution of the atmosphere, diet and drinking water can prevent the physical, chemical, parasitic and viral carcinogenic factors from attacking the human body and effectively prevent the occurrence of cancer. Secondary prevention is to reduce the death of cancer patients by using effective means of early detection, early diagnosis and early treatment. Its goal is to prevent the development of incipient disease. General survey, gastroscopy and upper gastrointestinal imaging can detect gastric cancer at an early stage. Therefore, once cancer is found, one should go to a specialized oncology hospital for diagnosis and treatment in time, actively cooperate with the treatment and believe in science to establish confidence that cancer can be overcome. Tertiary prevention refers to clinical prevention or rehabilitative prevention, which seeks to prevent cancer recurrence and metastasis, reduce complications and improve the quality of life when treating cancer. At present, oncology specialized hospitals are equipped with a complete set of scientific and comprehensive treatment means; patient-centered, individualized treatment is adopted according to the different conditions of tumor patients. For example, the organic combination of surgery, chemotherapy, radiotherapy and biological therapy.