Objective To investigate the cytotoxicity of cytokine induced killer (CIK) and natural killer (NK) cells derived from human peripheral blood on MDA-MB-231 breast cancer in vitro. Methods The MDA-MB-231 human breast cancer cells were infected with lentivirus containing red fluorescent protein (RFP) and luciferase (Luc) genes. The expression of RFP and Luc genes were detected by florescence microscopy. Peripheral blood mononuclear cells (PBMCs) were isolated from the patients to induce the information of dendritic cells (DCs), CIK and NK cells. Then DCs and CIK cells were co-cultured to induce the formation of DC-CIK cells. The amplification effect and the immunophenotypes of immune cells were detected by flow cytometry. And then the cytotoxicity of immune cells DC-CIK, CIK and NK cells on MDA-MB-231 breast cancer cells were analyzed at different effector-target ratios. Results he effects of DC-CIK, NK and CIK cells on MDA-MB-231 tumor cells increased with the increase of effector-target ratio and the extension of action time. After co-culture of 72 hours, the killing rate of immune cells on target cells reached more than 90%. Conclusion CIK, DC-CIK and NK cells amplified in vitro have apoptosis effects on breast cancer cells.