Objective To enhance the anti-tumor efficiency of artemisinin and to explore the anti-tumor and sensitivity-enhancing mechanism of Artemisinin Sensitizing Compound(ASC).Methods The growth-inhibition rate of HepG2 cells was determined by methyl thiazolyl tetrazolium(MTT) method.Tumor-bearing nude mice were given inoculation of HepG2 cells subcutaneously.After treatment for 15 days,the tumor-inhibition rate was calculated according to the tumor mass weight.Results The growth-inhibition rate of tumor cells in ASC group(artesunate combined with diethyl maleate,mercaptosuccinic acid and aminotriazole),was increased 43.84%,and the tumor-inhibition rate was three times as much as that in artesunate alone group with the same titer.The amount of antioxidant agents and the activity of antioxidant enzymes were higher in the control group than those in the artesunate alone group and ASC group,while were lower in ASC group than those in the artesunate alone group.Conclusion ASC has anti-tumor and sensitivity-enhancing effect through decreasing the amount of anti-oxidant agents and inhibiting activities of anti-oxidant enzymes.