Ultrafine WC powder was chosed and ultrafine crystalline gradient cemented carbides was prepared by a two-step sintering process, where the cemented carbides is first lower pressure pre-sintered and then subjected to a gradient sintering. The influences of cubic phase on microstructure and property of ultrafine crystalline gradient cemented carbides have been studied. The results show that the thicker gradient layer can be form in alloy with only adding Ti(C,N), but the mean WC grains size has a large value after gradient sintering. The thinner gradient layer has been formed when (W,Ti)C or (Nb,Ta)C was added, but the mean WC grains size is smaller than the alloy with only adding Ti(C,N). Some WC grains with size above 1 μm has been formed in the alloy with adding (W,Ti)C after gradient sintering. The formation of the core-rim structure cubic phase can be prevent by adding (Ta,Nb)C.