Abstract: Objective To prepare and characterize ursolic acid lysinate,and to study the antitumor effect of ursolic acid lysinate on human hepatoma cell line Bel7402.Methods Ursolic acid lysinate was prepared by co-grinding 1:1 molar mixture of ursolic acid and lysine for 12 hours.Characterization of ursolic acid lysinate was achieved by powder X-ray diffraction and infrared spectroscopy techniques.High performance liquid chromatography (HPLC)method was used to study the solubilization of ursolic acid lysinate.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)method was used to assay the antitumor activity of ursolic acid lysinate.Results The solubility of ursolic acid lysinate was improved significantly as compared to ursolic acid in water.The antitumor activity on human hepatoma cell line Bel7402 of ursolic acid lysinate was enhanced significantly than that of ursolic acid.Conclusion The water solubility and antitumor effect on human hepatoma cell line of ursolic acid lysinate may be potentially useful for its application as a new pharmaceutical formulation in cancer treatment in the future.