The　sol-gel　doping　method　was　utilized　to　dope　the　rare　earth　oxide　powder　into　molybdenum.　Such　powders　were　sintered　by　spark　plasma　sintering　and　traditional　sintering　combined　with　compaction　method　for　fabricating　REO-Mo　cermet　cathodes.　SEM,　DTA　and　electron　emission　property　measurements　were　used　to　investigate　the　secondary　electron　emission　properties　of　the　materials.　The　results　show　that　the　emission　performance　of　the　materials　can　be　enhanced　by　symmetrical　distribution　of　rare　earth　oxides　and　the　refinement　of　structure.　However,　such　treatments　can＇t　reduce　the　activation　temperature　in　vacuum.　Compared　with　the　un-treated　samples,　the　obvious　drop　of　activation　temperature　and　increase　of　secondary　electron　yield　occur　in　samples　annealed　at　high　temperature　in　hydrogen.　The　activation　temperature　decreases　obviously,　and　the　secondary　electron　emission　yield　is　enhanced　apparently.　Such　easy　adsorption　of　moisture　and　gas　in　the　REO　lead　to　oxidation　phenomena　of　molybdenum　in　the　subsequent　activation　in　vacuum.　The　hydrogen　annealing　technology　eliminates　the　excess　moisture　and　gas　and　retain　the　distribution　of　REO　in　molybdenum.　This　is　the　main　reason　of　variation　of　secondary　electron　emission　for　un-treated　samples　and　pre-activating　samples.