Abstract: MicroRNAs （miRNAs）are a class of small non-coding RNA that regulate their target gene expression at the post-transcriptional level. Functional study of miRNAs have shown that miRNAs have significant effect on chemotherapy resistance，radiotherapy sensibilization，angiogenesis，gene methylation， diagnosis and prognosis in gastric cancer. MiRNAs may shed new lights on the therapy for gastric cancer. This review will elaborate fundamental research of miRNAs in the chemoradiotherapy，diagnosis and prognosis of gastric cancer.