Objective:To evaluate effects of different factors on proliferation capacity and cytotoxicity of induced cytokine induced killer(CIK)cells in vitro,so as to provide experimental basis for cell therapy of CIK in tumor.Methods:Cytometry and MTT assay were used in detecting proliferation capacity and cytotoxieity of CIK.Results:The proliferation capacity and eytotoxicity of CIK in vitro were stronger in the group of low age and serum free medium than in the group of advanced age or serum medium.And the proliferation of CIK in vitro increased with time during a certain period of incubation.Furthermore,CIK had equal cytotoxieity to various tumor cells. Conclusion:Various factors might influence the proliferation capacity and cytotoxicity of CIK of tumor patients in vitro.