The exact cause of gastric cancer is not very clear, but it is related to the following factors: first, geographical environment, the incidence of gastric cancer in northwest and east coast of China is significantly higher than that in south. Firstly, geographical environment, the incidence rate of stomach cancer in northwestern and eastern coastal regions is significantly higher than that in southern regions. Secondly, dietary factors, the incidence of gastric cancer is significantly higher among people who consume smoked and pickled foods for a long time. Thirdly, patients infected with H. pylori is one of the important factors triggering gastric cancer. Fourthly, patients suffering from chronic diseases and precancerous lesions, that is, patients suffering from gastric polyps, chronic atrophic gastritis and residual stomach after partial gastrectomy, are also the high incidence of gastric cancer. Fifthly, genetic and genetic factors, the incidence rate of stomach cancer is about 4 times higher among the blood relatives of stomach cancer patients than normal people.