H. pylori is listed as the first group of carcinogen for gastric cancer, but even negative H. pylori can get gastric cancer. Because gastric cancer is the result of many factors, it is also related to the following factors: 1. diet, poor dietary habits and lack of various nutrients are risk factors for the development of gastric cancer, such as preferring hard food, hot food, moldy food, pickled food, etc. 2. bad hobbies, smoking is closely related to gastric cancer because there are also carcinogens such as polycyclic aromatic hydrocarbons and specific nitrosamides in tobacco. 3. heredity, patients with family history of gastric cancer are four times more likely to develop gastric cancer than those without family history. 4. Patients with family history of gastric cancer are four times more likely to develop gastric cancer than those without family history.4. Psychosocial, mental stimulation, depression and poor psychological regulation are also risk factors of gastric cancer.