Anisotropic　nanocrystalline　Sm0.6Pr0.4Co5　magnets　were　successfully　prepared　by　spark　plasma　sintering　hot　pressing　and　hot　deformation　technique.　The　magnetic　properties　of　the　hot　deformed　Sm0.6Pr0.4Co5　magnet　were　optimized　by　adjusting　the　hot　deformation　temperature.　The　microstructure,　c-axis　texture,　temperature　stability　and　magnetic　hardening　mechanism　of　the　optimized　magnets　were　systematically　studied.　As　a　consequence,　an　unprecedentedly　high　energy　product　of　21.10　MGOe　has　been　achieved　in　the　single　phase　hot-deformed　magnet,　which　is　the　highest　value　as　ever　reported,　indicating　the　great　application　potential　for　extreme　environments　of　hot　deformed　Sm0.6Pr0.4Co5　magnet.　©　2021