Nanostructured W-La2O3 electrode materials with a high content of La2O3 have been prepared by mechanical alloying (MA) and hot pressing and sintering (HPS). An investigation has been made on operation characteristics for nanostructured W-La2O3 cathodes. The service lifetime of the nanostructured W-La2O3 cathode is longer than that of commercially used W-2wt.% La2O3 cathodes. These operation characteristics depend on the content of the rare-earth oxide. Specially, the content of La2O3 governs resistance to arc erosion of the electrodes.