Abstract: Using the cemented carbide raw materials without nitrogen, the graded cemented carbide with cubic carbide free layer (CCFL) in the surface zone was prepared by means of gradient sintering at 1 420,1 450,1 480 ℃ for 1 h, respectively, where one micro pressure (0.5 kPa) nitriding sintering (MPNS) step was added prior to usual gradient sintering procedure. In addition, the cemented carbide with heterogeneous structure was prepared without MPNS. The microstructure, phase composition and element distribution of the cemented carbides were investigated by SEM, XRD and EDS. The results show that, the thickness of cubic carbide free layer was 8,13,24 μm under the above sintering process conditions. The phases and chemical compositions distribution regular of the graded cemented carbide with CCFL were basically same with that of the graded cemented carbide prepared by raw materials with nitrogen, that is to say,there were only two phases including WC and Co phases in the CCFL, whereas there were WC, (Ti,W)C and Co phases in the core zone, and the titanium content in the CCFL was close to zero, cobalt content was apparently higher than that in the core zone, whereas there was only tiny fluctuation of tungsten content.