Dense　Si3N4/BN　composite　ceramics　were　fabricated　by　SPS　at　1600-1650°C　for　5　minutes.　Experimental　results　indicate　the　SPSed　Si3N4/BN　composite　ceramics　maintains　a　considerably　high　bending　strength,　though　it　has　a　gradual　decrease　with　increasing　BN,　caused　by　the　aggregation　of　h-BN　grains.　The　bending　strength　of　sample　was　nearly　900　MPa　when　BN　content　got　up　to　30%,　which　could　be　highly　machined　by　WC　tool　as　well.　SEM　analysis　suggests　that　microstructures　of　the　materials　are　optimized　during　SPS　process,　which　play　a　key　role　in　the　improvement　of　strength.