Abstract: Objective To study the effects of IL-24 on cytotoxic activity of cytokine-induced killer cells in vivo.Methods (1)Mononuclear cells were extract from health adult peripheral blood.one group added IFN-γ(1000IU/mL)at the first day and IL-1(100IU/mL)、CD3mAb(50ng/mL)、IL-2(300IU/mL)at the second day.The other group added IL-24(1000IU/mL)at the same time with IL-1、CD3mAb、IL-2;(2)Tumor-bearing mice were divided into five groups,and tumor volumes were measured every three days.Results The solid tumor volumes of IL-24 induced group are smaller than other groups(P＜0.05).Conclusion Added IL-24 during induced procedure can obviously enhance the cytotoxic activity of CIK cells in vivo.