Objective Co-stimulation cells is a kind of natual killer (NK)-like T cells, which can kill tumor cells.Previous studies show that lupeol , an natural plant extracts , can change the growth of NK cells ,γδT cells and their effects on tumor cells .This study aimed to investigate the effects of lupeol on human co-stimulation cells and colonic cancer cell lines SW 480 . Methods The peripheral blood mononuclear cells ( PBMC) from healthy volunteers were induced in vitro by different cytokines and transferred into Co-simulation cells.After SW480 and Co-stimulation cells were incubated with different concentrations of lupeol for different durations , methyl thiazolyl tetrazolium (MTT) was used to detect the effects of lupeol on co-stimulation cells and colonic cancer cell lines SW480. Lactate dehydrogenase was used to determine the cell-killing activity of Co-simulation cells to colonic cancer lines SW 480 . Results The concentration of lupeol in 0.1-200.0 mg/L promoted the growth of Co-stimulation cells and inhibited the colonic cancer cell lines SW480.When the concentration of lupeol is at 12.5 mg/L, the cell-killing activity of Co-simulation cells to colonic cancer lines SW 480 was enhanced significantly compared with the controls (76%vs 40%, P<0.05). Conclusion Lupeol could promote the prolifera-tion of Co-stimulation cells, inhibit the growth of cancer lines SW480, and strengthen the cytotoxicity of Co-stimulation cells against co-lonic cell lines SW480.