The　full　densification　polycrystalline　cerium　hexaboride　(CeB6)　cathode　material　was　prepared　by　using　the　spark　plasma　sintering　(SPS)　method　in　an　oxygen　free　system.　The　starting　precursor　nanopowders　with　an　average　grain　size　of　50　nm　were　prepared　by　high-energy　ball　milling.　The　ball-milled　nanopowder　was　fully　densified　at　1550　degrees　C　under　50　MPa,　which　was　about　350　degrees　C　lower　than　the　conventional　hot-pressing　method　and　it　was　also　lower　than　that　of　coarse　powder　under　the　same　sintering　condition.　The　mechanical　properties　of　nanopowder　sintered　samples　were　significantly　better　than　that　of　coarse　powder,　e.g.,　the　flexural　strength　and　Vickers　hardness　were　211%　and　51%　higher　than　that　of　coarse　powder,　respectively.　The　electron　backscattered　diffraction　(EBSD)　result　showed　that　the　(100)　fiber　texture　could　be　fabricated　by　the　ball-milled　nanopowder　sintered　at　1550　degrees　C　and　the　thermionic　emission　current　density　was　measured　to　be　16.04　A/cm(2)　at　a　cathode　temperature　of　1873　K.