The　LaH2　and　PrH2　nanopowders　were　prepared　by　hydrogen　arc　plasma　method,　and　then　dense　single-phase　polycrystalline　La0.4Pr0.6B6　bulks　were　reactively　fabricated　starting　from　mixture　of　synthesized　LaH2,　PrH2　nanopowders　and　boron　powders　by　spark　plasma　sintering　(SPS).　The　influence　of　SPS　sintering　temperature　on　the　microstructure　and　properties　was　investigated.　Thermionic　emission　measurement　of　the　sample　sintered　at　1400　degrees　C　and　40MPa　was　performed.　It　is　shown　that　the　pure　phase　La0.4Pr0.6B6　bulk　can　be　easily　fabricated　by　SPS　when　the　sintering　temperature　is　higher　than　1350　degrees　C　and　the　density　of　the　material　increases　with　increasing　temperature.　The　largest　values　of　densities,　Vickers　hardness　and　bend　strengths　reach　4.82g/cm(3),　19.14GPa　and　225.13MPa,　respectively.　The　largest　emission　current　density　of　the　cathode　heated　at　1873K　is　30.65A/cm(2).　The　work　function　at　absolute　zero　is　calculated　to　be　2.165eV　by　Richardson　line　method,　and　then　the　average　value　of　effective　work　functions　of　the　cathode　at　different　temperatures　are　calculated　to　be　2.84eV.