Abstract: Gastric cancer is one of the most common cancers with poor prognosis. miRNA is a kind of non-coding RNA with a length of 18-25 nucleotides. miRNAs contribute to gastric cancer by altering expressions of oncogenes and tumor suppressors to affect cell proliferation, apoptosis, and metastasis and invasion. In addition, miRNA shows clinical significance in the diagnosis, prognosis prediction and treatment of gastric cancer. In this paper, the mechanism and clinical significance of miRNA in gastric cancer are reviewed.