To prevent gastric cancer, the following examinations are recommended: 1) H. pylori examination, because H. pylori is very closely related to gastric cancer according to research; 2) Gastroscopy is the most valuable examination, which can detect most of the patients with early gastric cancer; 3) Some traditional methods are less used now, such as barium gastric meal imaging; 4) Serological examination can be done for some high-risk groups, such as gastrin examination, and of course, tumor markers that are more sensitive to the gastrointestinal tract. The test also has different significance. From the doctor’s point of view, for male patients over 40 years old, the above mentioned examinations should be done 1-3 years, so that gastrointestinal tumors can be detected early. Early detection of gastrointestinal tumors is very important because early detection is closely related to the treatment effect. For example, early detection of early gastric cancer in patients with gastric cancer has completely different consequences from late detection of progressive gastric cancer, and the 5-year survival rate is much different. Therefore, early detection and early treatment are emphasized. There are more methods available clinically for early gastrointestinal tumors, especially gastric cancer. It is recommended that high-risk groups, i.e. those with family history of gastric cancer, areas with high incidence of gastric cancer, and those who like to eat unhealthy foods such as pickled foods, are recommended for early examination, early detection and early treatment.