Abstract: Objective To explore the effect of oxidative stress on the apoptosis of HEK293 cells induced by cadmium.Methods The apoptosis were measured by flow cytometry,and the content of cytosolic reactive oxygen species(ROS)were measured respectively by flow cytometry and confocal laser microscopy.The HEK293 cells homogenates were pr epared to detect the levels of malondialdehy de(MDA)and reduced glutathione hormone(GSH)in spectro photometric assay.Western blot was used to analyze the expressions of Bcl-2 and Caspase-3 proenzyme.Results The rate of apoptosis exhibited in the dose-dependent manner in definite CdCl₂ concentrations extent.After six hours with treatment 60 μmol/L CdCl₂ ,the rate of apoptosis was in peak,the levels of cytosolic ROS and MDA increased and the level of GSH decreased significantly(P<0.01).The expr ession of Bcl-2 was lower compared with three-hour treatment with 60 μmol/L CdCl₂,and the expression of Caspase-3 proenzyme decr eased compared with the co ntrol.Conclusion Cd-induced apoptosis involves enhancive ROS,oxidative injury,the expression of Bcl-2 down regulation and the activation of Caspase-3 in HEK 293 cells.