Ultrafine-grained WC-Co bulk materials were prepared by a new method that contains pretreaent of the milled powder mixture and sub-sequent spark plasma sintering (SPS). Ball milling parameters and the pretreatment temperature have significant effects on the microstructure and properties of WC-Co cermets. The prepared cermets have a mean grain size of less than 0.5 μm even with a pretreatment temperature as high as 1300℃. The WC-10wt.%Co cermet bulk prepared by the optimized milling, pretreatment, and SPS processing achieves excellent mechanical properties with a Vickers hardness of HV 1643, a fracture toughness of 13.1 MPa-m1/2and a transverse rapture strength of 3100 MPa.