The formation of gastric cancer is related to multiple factors, such as genetics, diet, and multiple diseases of the stomach, and there is no clear definition of the exact time of occurrence. Gastric cancer is one of the most common tumors in the gastrointestinal tract other than rectal cancer. The specific cause of the occurrence of gastric cancer is not clear, but epidemiology has found that it is related to long-term H. pylori infection as well as long-term stimulation of dietary factors and genetic factors. It is clinically found that long-term H. pylori infection is directly related to gastric cancer, and families with genetic factors are 2-3 times more likely to have family members with gastric cancer than the general population. In addition from gastric ulcer, atypical hyperplasia, precancerous lesions and other time periods some years, decades or forever hair will not occur cancer, so the exact time is not certain. It is recommended to pay attention to diet in daily life, avoid strain and spicy and stimulating food, and at the same time, actively treat H. pylori infection.