Agglomerate sintered and blended NiCrAlY-Y2O3 cermets were prepared from NiCrAlY and Y2O3 powders by two process routes. The particle morphologies and powder characteristics of both cermets feedstock using for thermal spraying were investigated. Both types of NiCrAlY-Y2O3 cermets and one commercial CoCrAlY-Y2O3 cermets were HVOF thermal sprayed onto the stainless steel substrate to obtain coatings having a thickness about 100 microns. Porosity and thermal shock resistance of coatings were examined. Four thermal sprayed coatings were comparatively evaluated build-up resistance by contacting reaction with MnO, Fe3O4 powders and manganese bearing carbon steel statically at high temperatures. The agglomerate sintered NiCrAlY-Y2O3 coatings have good resistance to manganese oxide build-up but bad resistance to iron oxide build-up. The agglomerate sintered cermets coating has better build-up resistance than blended cermets coating.