Abstract: Objective To understand the mechanism of mitochondria path way of apoptosis induced by arte sunate combined therm otherapy in human lung adenocarcinoma A 549 cell line.Methods Lung adenocarcinoma A 549 cell line was treated with ar tesunate(150μmol/L)and hypertherm ia(43℃ for 1h)for 24 h.Cell cycle and the apoptosis rate were measured by flow cyto metry assay(FCM).Mitochondria membrane potential was observed with JC-1 apoptosis detection kit by fluo rescence microscope.The prote in expressions of cyto chromec,Bcl2 and caspase 3 in A 549 cell line were assessed with western blot and mimunocy to chemical method.Expression of active caspase 3 was a ssayed by CaspA CETM assay system.Results Compared with the control,the number of cell increased in stage G0/G1 and decreased in stage S and G2/M with statistic difference(P<0.01).The apoptosis rate of A 549 cell line treated with artesunate,artesunate and ther motherapy increased to 16.77% and 28.90% compared with 2.08% of the control with statistic difference(P<0.01).Rates of mitochondria membrane potential decrease were 18.05% and 50.98% in A549 cell treated with rate sunate,and artesunate plus hyperthermia respectively compared to 1.92% in control A549 cell(P<0.01).Protein expression of cytochromec and caspase 3 increased,while expression of Bcl2 decreased compared to control group(P<0.01).Expression of active caspase 3 increased to 0.2641±0.0027 and 0.3613±0.0019 with statistic difference(P<0.01).Conclusion Artesunate and ther motherapy has an effect of inducing apoptosis in human lung adenocarcinoma A549 cell line.The activation of mitochodria path way may be an important mechanism for cell apoptosis.