Barium　calcium　aluminate　(4BaO:CaO:Al2O3)　was　synthesized　via　liquid　phase　co-precipitation　and　solid　phase　mixing　respectively　and　sintered　in　hydrogen　atmosphere.　Scandia　doped　tungsten　powders　were　prepared　in　a　new　process　of　spray　drying　combined　with　two-step　hydrogen　reduction.　During　the　preparation　of　scandia　doped　impregnated　cathodes,　a　series　of　procedures,　including　pressing,　sintering,　impregnating,　water　cleaning　and　annealing　were　taken　to　obtain　the　impregnated　cathodes.　The　results　show　that　Ba5CaAl4O12　is　formed　after　high　temperature　sintering.　After　impregnation,　scandia　doped　impregnated　cathodes　with　porous　sub-micron　structure　are　obtained.　For　full　activation　at　1150　degrees　C,　the　cathode　surface　is　covered　by　a　Ba-Sc-O　active　substance　layer　with　a　preferable　atomic　ratio,　leading　to　its　good　emission　property　with　space　charge　limited　current　density　of　37.89　A/cm(2)　at　850　degrees　C.