Stomach cancer is a common malignant tumor that seriously threatens human health. Japan, Korea and China in Asia are the regions with high incidence of gastric cancer, and there are about 400,000 new cases in China every year, accounting for 42% of the total number of cases in the world. Studies have found that gastric cancer has become the most common malignant tumor in China in terms of incidence and mortality by 2005. According to the latest statistics, although the global incidence rate of gastric cancer has shown a general decreasing trend in the past 10 years, its mortality rate still ranks the second highest in the world. Risk factors are important in the prevention and treatment of gastric cancer. Epidemiological and related studies show that environmental and dietary factors, infectious factors, and host factors are all closely related to gastric cancer. Dietary factors Nitrosamine pathogenesis is the classical doctrine of gastric cancer development. Improper diet and smoking expose people to the effects of nitroso compounds and increase the risk of gastric cancer pathogenesis. The amount of nitrosamines present in natural foods is very little, and exogenous nitrosamines are mainly obtained through the intake of cured and preserved meat foods, smoked foods and preserved foods, so it is important to reduce the intake of related foods. The role of alcohol in promoting gastric cancer should also not be ignored. The World Health Organization regards acetaldehyde produced by endogenous ethanol as a class I carcinogenic factor. Acetaldehyde is a key intermediate substance in alcohol fermentation and ethanol oxidation, and it is also the most carcinogenic substance contained in tobacco. Therefore, controlling the intake of tobacco and alcohol can significantly reduce the incidence and mortality of gastric cancer. Infection factors Hp infection is closely related to the occurrence of gastric cancer, and Hp-induced inflammation is one of the risk factors for gastric cancer. Areas with high prevalence of gastric cancer also have high rates of Hp infection, but not all infections lead to gastric cancer. Targeted clearance of Hp infection can not only reduce the incidence of gastric cancer, but also have a positive effect on the recovery of chronic gastritis. Host factors Host factors, i.e. individual patient factors, are complex in the development of gastric cancer and are usually associated with changes in related genes. Oncogenes promote gastric cancer. When gastric cancer is found, early medical examination and finding targeted drugs can effectively curb the development of gastric cancer. Chronic atrophic gastritis is classified as a precancerous disease or pre-cancerous state of gastric cancer, while intestinal epithelial hyperplasia and heterogeneous hyperplasia accompanying on its basis are called precancerous lesions of gastric cancer, and the above factors are both risk factors for the occurrence of gastric cancer and causative factors leading to atrophic gastritis. Effective correction of poor lifestyle, regular review of H. pylori and identification of target genes that play a key role in gastric cancer can play a positive role in reducing the incidence of gastric cancer and improving its prognosis.