High-quality　single　crystals　Ce1-xPrxB6　(x　=　0.1,　0.2,　0.4)　hexaborides　were　successfully　prepared　by　the　reactive　spark　plasma　sintering　(SPS)　combining　with　the　floating　zone　melting　method　using　powder　of　CeB6　and　PrB6　as　raw　materials.　The　thermionic　emission　properties　of　the　(100)　plane　of　single　crystals　were　investigated.　Results　show　that　the　(100)　plane　of　Ce0.8Pr0.2B6　single　crystal　has　the　maximum　emission　current　density,　66.07　A/cm(2)　at　1873　K,　which　is　higher　than　the　current　reported　CeB6　single　crystal,　increased　by　about　20%.　In　addition,　the　thermal　emission　current　density　of　(100)　plane　of　Ce0.9Pr0.1B6,　Ce0.6Pr0.4B6　single　crystals　are　65.81　A/cm(2)　and　65.31　A/cm(2),　respectively.　The　(100)　plane　of　Ce0.8Pr0.2B6　single　crystal　has　the　lowest　work　function　of　2.61　eV,　while　the　work　functions　of　other　single　crystals　are　in　the　range　of　2.64-2.753　eV.　Therefore,　single　crystals　Ce1-xPrxB6　hexaborides　have　good　thermionic　emission　and　low　work　function,　which　promises　good　prospects　in　the　application　as　a　hot　cathode　material.