The　polycrystalline　Pr1-xCexB6　(x　=　0.2,　0.4,　0.6,　0.8)　hexaborides　are　prepared　by　the　reactive　spark　plasma　sintering　(SPS)　method　using　mixed　powder　of　CeH2,　PrH2　and　B.　The　effects　of　Ce　doping　on　the　phase　composition,　the　mechanical　properties　and　the　thermionic　emission　properties　of　the　hexaboride　are　investigated.　The　single-phased　hexaborides　CexPr1-xB6　bulks　are　sintered　at　a　temperature　of　1450　degrees　C,　pressure　of　50MPa　and　holding　time　of　5　mm,　and　the　sintered　samples　show　high　value　of　Vickers　hardness　(24.34　GPa)　and　bend　strength　(226.02　MPa).　The　thermionic　emission　results　show　that　with　the　increase　of　Ce　content,　the　thermionic　emission　current　density　increases　linearly　and　the　maximum　value　of　Pr0.4Ce0.6B6　reaches　47.3　A.cm(-2)　under　an　applied　voltage　of　950　V　at　1973　K,　which　is　much　higher　than　that　obtained　by　traditional　method.　Thus,　the　SPS　technique　represents　a　suitable　method　to　synthesize　the　dense　rare-earth　hexaborides　with　excellent　properties.