Gastric cancer is common as one kind of digestive tract malignant tumor, and Helicobacter pylori (Hp) infection is the most important cause of gastric cancer. With the wide application of quadruple therapy, the incidence of Hp-related gastric cancer has been significantly decreased. In addition to the involvement of gastric microbes in the regulation of normal gastric physiological function, the imbalance of gastric microbes is also involved in the pathogenesis of gastritis and gastric cancer. The imbalance of gastric microbes also plays an important role in the development of gastric cancer after eradication of Hp, and the mechanism has also been preliminary studied. Based on this, this article reviews the research progress of gastric microbes in gastric cancer, in order to further understand the pathogenic mechanism of gastric cancer and provide reference for seeking safer and more effective treatment for gastric cancer.