Abstract: Objective To investigate the effect of Lycopene on the apoptosis of human colon cancer SW480 cells and the relevant molecular mechanism. Methods The anti-proliferative effect of a different concentration of Lycopene on SW480 cells was measured by MTT assay.Ratio of SW480 cells apoptosis was analyzed by flow cytometry.The levels of Bcl-2,Bax were detected by RT-PCR and Western blot.The expression levels of Caspase-9 and Caspase-3 were analyzed by Western blot. Results The MTT assay showed that Lycopene had potent anti-proliferative effect on SW480 cells in a time- and dose-dependent manner.The IC50 value of Lycopene was SW480 cells treated with 1.0 μmol/L Lycopene for 24 hours.Flow cytometry analysis revealed that Lycopene increased the percentage of apoptotic SW480 cells.The expression level of Bcl-2 were decreased,while the expression levels of Bax,Caspase-9 and Caspase-3 were increased significantly in SW480 cells treated with different concentrations of Lycopene. Conclusion Lycopene could induce apoptosis of SW480 cells by decreasing the ratio of Bcl-2/Bax and increasing Caspase-9 and Caspase-3 expression.