Gastric cancer is a major malignant tumor worldwide. Currently, lots of researches confirm that as a cancer suppressor gene, miR-146a can promote the degradation of mRNA and inhabit the synthesis of proteins, so as to maintain normal physiological metabolism function in cells. But the expression of miR-146a decreases in the progression of gastric cancer, resulting in losing normal control for many signaling pathways in cells and promoting the proliferation and metastasis of cancer cells. The molecular mechanism of influencing the progression of gastric cancer by miR-146a is still unclear. This paper reviews research advances on this topic and relevant clinical applications.