Abstract. In order to explore the regulation of the invasive ability of hepatocellular carcinoma cells and the underlying mechanism, mimics sequences of microRNA (miR)-125a (miR-125a-3p/5p) and scramble sequences (miR-125a-3p-s/5p-s) were transfected into human hepatocellular carcinoma cell lines, HCC-LM3 and HepG2, and the non-malignant epithelioid hepatic cell line QZG. To inhibit and upregulate the expression of miR-125a individually. Protein expression was detected by western blotting, and the cell proliferation and migration abilities were evaluated by soft agar colony formation and Transwell assay, respectively. It was revealed that the expression of miR-125a was downregulated in HepG2 and HCC-LM3 cells compared with that of QZG cells, and expression was markedly lower in HCC-LM3 cells than that in HepG2 cells (P<0.01). The colony formation and migration rates of the cells transfected with miR-125a-3p/5p were decreased compared with negative controls, but were increased in cells transfected with miR-125a-3p-3/5p-s (P<0.01). The protein and messenger RNA expression of phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) was decreased following transfection with miR-125a-5p, whereas expression was increased compared with negative controls following transfection with miR-125a-5p-s (P<0.01). Furthermore, the proliferation and migration abilities of cells were attenuated following inhibition of the PI3K/AKT/mTOR pathway by LY294002. The results of the present study indicated that miR-125a inhibits the invasive ability of hepatocellular carcinoma cells via regulation of the PI3K/AKT/mTOR pathway.