objective:to investigate the cytotoxic effects of human peripheral blood γδt cells on lung cancer cell lines a549. methods:the γδt cells in peripheral blood of healthy volunteers were cultured using interleukin－2(il－2)and isopentenyl pyrophodphate (ipp)in prmi1640 medium. The purity of γδt cells was analyzed by flow cytometry .the cytotoxic activity of the purified γδt cells against human lung cancer cell lines a549 was tested in different effector－to－target ratios (t/e ratios). Results:γδt cells were obtained with a high purity from peripheral blood mononuclear cells,the cytotoxic effects of γδt cells on a549 depended on γδt cells’ purity and effector－to－target ratios. When effector－to－target ratios and purity of γδt cells increased,the cytotoxcity effect on a549 increased. Γδt cells showed more remarkable cytolysis than cik cells. Conclusion:γδt cells of human peripheral blood could significantly kill lung cancer cell lines a549 in vitro.