Objective: To investigate the miR-449a expression in hepatocellular carcinoma (HCC) cells and its effect on biological behaviors of HCC cells. Methods: The miR-449a expressions in normal hepatic L02 cells and 4 types of HCC lines (HepG2, Hep3B, SMMC-7721 and Bel-7402) were determined by qRT-PCR method. HCC cells were transfected with miR-449a mimics or scrambled sequences via lipofection, and then, the changes in cell proliferation, cell cycle and invasion ability were detected by CCK-8 assay, flow cytometry and Transwell assay respectively; moreover, the tumor formations of the HCC cells with above transfections in nude mice were observed. Results: The miR-449a expression levels in the 4 HCC cells were all significantly lower than those in L02 cells (all P<0.05), and showed the lowest level in Bel-7402 cells. Compared with Bel-7402 cells transfected with scrambled sequences, the proliferative activity was significantly inhibited, G1/S phase arrest was significantly increased, and the number of migrating cells was significantly decreased in Bel-7402 cells transfected with miR-449a mimics (all P<0.05). The weight and volume of xenografts derived from Bel-7402 cells transfected with miR-449a mimics in nude mice were all decreased compared with those derived from Bel-7402 cells transfected with scrambled sequences (0.748 g vs. 1.234 g; 33.667 mm3vs. 1 400.500 mm3, both P<0.05). Conclusion: The miR-449a expression is decreased in HCC cells, and up-regulating miR-449a expression can suppress the growth of HCC cells in vivo and in vitro.