Objective To observe the effect of a wide range of concentration of arsenic trioxide on hepatoma cell line BEL-7402 with variable duration. Methods The cell activity and morphologic changes were studied after treated with different concentration. The apoptosis were detected by flow cytometry assay and DNA Gel electrophoresis. Results The effect of arsenic trioxide on hepatoma cell lines were dependent on the time and concentration obviously. Hepatoma cells cultured with different concentration presented apoptosis features: i.e. intact cell membrane, chromatin condensation, nucleic fragmentation and apoptotic body formation; flow cytometry analysis showed an arrestment at G2/M phase and a subG1 cell peak, DNA gel electrophoresis showed a marked DNA ladder. Conclusion Arsenic trioxide can obviously inhibit the growth of hepatoma cell lines through inducing hepatoma cell apoptosis.