ObjectiveTo detect the expression of microRNA-497(miR-497) in gastric cancer and its biological significance, and to find out its regulatory links with other genes and investigate the effect of miR-497 overexpression interference on chemotherapy sensitivity of gastric cancer cell line. MethodsNinety-four gastric cancer tissues and adjacent to cancer tissues from 2010 to 2013 in this hospital were collected. The expression of miR-497 in the gastric cancer tissue or adjacent to cancer tissue was detected by real-time PCR. SGC-7901 cell line was transfected by miR-497-negative control and miR-497-mimics, respectively. The BCL2L2 expression was measured by Western blot after upregulation of miR-497. The chemotherapy sensitivity of cell line was tested by MTT assay. Results①The expression of miR-497 was significantly downregulated in the gastric cancer tissues as compared with the adjacent to cancer tissues (P < 0.01). 2 BCL2L2 was predicted to target gene of miR-497. after miR-497 overexpression in cells, the expression of BCL2L2 protein was decreased in the miR-497-mimics cells as compared with negative control cells. The IC50 in the miR-497-mimics cells was significantly lower than that in the negative control cells(P=0.004 6). ConclusionsmiR-497 expression is frequently downregulated in gastric cancer tissue. Overexpression of miR-497 could inhibit the expression of target gene BCL2L2, and improve chemotherapy sensitivity of gastric cancer cell line, which implies that miR-497 may play an important role in carcinogenesis and therapy of gastric cancer.