Abstract: Objective : The apoptosis of A549 human lung adecarcinoma cell line and PLA-801Dhuman lung giant cell cancer cell line induced by anticancer ketonon was studied in order to explore itsmechanism of antineoplastic effect. Methods : By techniques of cell culture in vitro,lung cancer cellswere treated by anticancer ketonon. Then observed and analysed by growth-curves,clone experimentand light microscopy. The expression of apoptosis-related gene was detected by flow cytometry. Results : The proliferation of A549 cells and PLA-801D cells was inhibited evidently after treatment byanticancer ketonon. Ability of clone formation was also inhibited. Apoptosis index was enhanced andcells were blocked at G₀/G₁, phrase (P<0.01). Bax and Fas expression was up-regulated (P<0.01) andBcl-2 expression was down-gulated(P<0.01). c-myc,TGF(3R 1 expression was up-regulated(P<0.01). Conclusions : Anticancer ketonon has remarkable cytotoxity and could induce the apoptosis of A549cells and PLA-801D cells by up-regulating expression of Bax and Fas and down-regulating expressionof Rcl-2.