Abstract: ObjectiveTo observant the dose effects of Siwu Mixture on the apoptosis in HL-60 leukemic cells by myleran. MethodsHL-60 leukemic cells proliferation was tested by MTT assay,cell apoptosis was analyzed by flow cytometry,the p53/bcl-2 expression was assessed by Western blot, cytochrome C release was determined by ELISA,GSH,Caspase-3 and Caspase-8 activation were examined by colorrimetric assay. ResultsSiwu mixture could increase HL-60 leukemic cell apoptosis by myleran,upregulated ratio of p53/bcl-2 expression,activated of Caspase-3 and Caspase-8,increased the release of cytochrome C,decreased the levels of GSH（P＜0.05，P＜0.01）,and inhibited the growth of HL-60 leukemic cells at the dose of 60mg/L(P＜0.05). ConclusionSiwu mixture was able to inhibit the growth of HL-60 leukemic cells,enhance antitumor effect of myleran and the major mechanism siwu mixture's promotion sensitivity of tumor cell to chemotherapeutic agents might be related to activat apoptosis signal pathway.