Objective To study the inhibitory effect and mechanism of citrusinol on proliferation of human hepatocellular carcinoma cells HepG2.Methods The inhibitory rate of HepG2 cells cultured in vitro was measured by MTT assay.The morphology and distribution of the ceils were observed by HE and acridine orange staining.The cell division cycle was detected by flow cytometry.The expression of F-actin protein was observed by fluorescent chromogenic method.Results Citrusinol could inhibit the growth of HepG2 cells,and the IC50 of the inhibitory rate was 76.46 μmol/L.Citrusinol could make the HepG2 cells shrink,arrest the cell division cycle to G2/M,and inhibit the expression of F-actin.Conclusion Citrusinol can prevent cell proliferation by arresting cell division cycle in G2/M phase and inhibiting the formation of cytoskeleton,thus inhibiting the growth of G2/M.