Isothermal oxidation resistance,oxide scale evo-lution and failure mechanism of Ce-doped Co-Al-W-Mo-Ta-B alloy (0.01 at％,0.05 at％,0.10 at％ and 0.20 at％ Ce)exposed at 800 ℃ were compared.The 0.01Ce and 0.05Ce alloys were consisted of γ/γ\'coherent microstructure,while the κ-Co3W compound precipitated at the grain boundary of the 0.10Ce and 0.20Ce alloys in addition to the γ/γ\'microstructure.The oxidation kinetics curves of the Ce-doped alloys exhibited a parabolic time dependence on the weight gain.With an increasing nominal Ce content,the weight gain of the Co-Al-W-Mo-Ta-B alloys monotoni-cally decreased.An oxide scale composed of a dense and uniform outer Co3O4 + CoO layer,a middle CoAl2O4 and CoWO4 compound layer and an inner Al2O3 layer.The excellent oxidation resistance of 0.2Ce alloy was mainly attributed to a shorter incubation stage for the formation of the continuous and protective Al2O3 layer and the thickest Al2O3 layer during entire oxidation process.