Abstract: To investigate the inhibition effects of NO-donating oleanane derivative (SO-10) on human hepatoma cell lines and the antitumor activities of NO， MTT assay was used to analyze human hepatoma cells (HepG2,BEL-7402 and SMMC-7721) proliferation.SO-10 strongly inhibited human hepatoma cell proliferation and their IC₅₀values were 1.19±0.12 μmol/L for HepG2,1.98±0.85 μmol/L for BEL-7402 and 5.92±0.58 μmol/L for SMMC-7721 after 48 h.Apoptosis of HepG2 cells induced by SO-10 was detected by flow cytometry (FCM)，showing that SO-10 dramatically triggered apoptosis in HepG2 cells in a dose-dependent manner.The amount of NO produced by SO-10 were increased from 30 min to 6 h examined by the Griess assay.Furthermore,pre-treatment with different concentrations of hemoglobin notably reduced the concentrations of NO and inhibited the cytotoxicity of SO-10 against HepG2 cells.SO-10 showed remarkable effects of inhibiting cell proliferation and inducing apoptosis of human hepatoma cell lines.The significantly high concentrations of NO produced by SO-10 might contribute to its cytotoxicity against HepG2 cells.