Nanocomposite　Nd2Fe14B/SmCo5　permanent　magnets　with　different　weight　ratios　have　been　prepared　by　spark　plasma　sintering　mixtures　of　homemade　amorphous　SmCo5　powders　and　commercially　available　Nd2Fe14B　powders.　The　magnetic　properties　of　the　nanocomposite　magnets　are　sensitive　to　the　ratio　of　the　two　hard　phases.　The　peak　(BH)(max)　value　of　14.4　MGOe　is　obtained　at　the　SmCo5/Nd2Fe14B　ratio　of　4:1,　which　is　similar　to　50%　higher　than　that　of　the　single-phase　SmCo5　magnet　prepared　under　the　same　preparation　conditions.　Hysteresis　loop　of　the　nanocomposite　magnet　shows　the　characteristics　of　single-phase　magnet　due　to　strong　exchange　coupling　between　the　two　phase　grains.　At　high　temperatures,　the　nanocomposite　magnets　exhibit　greatly　improved　thermal　stability　compared　with　the　single-phase　Nd2Fe14B　magnet.