Theory of preparation of sub-micro WC particles reinforced Ni-base super alloy matrix composite using direct metal laser sintering (DMLS) is introduced. The effects of processing parameters ,such as laser power,scanning speed on the microstructures,composition and microhardness of the laser sintered samples were characterized by X-ray diffraction (XRD),scanning electron microscope (SEM ) and microhardness tester. The result shows that the examples prepared by laser sintering have better performance and higher density under the laser power of 900 W,scanning speed of 0.7 m/min,for WC particles melt as dendrites disperse evenly in the matrix and can be captured by solid-liquid interface. The compact metal bulks with high hardness are fabricated successfully by DMLS with optimized processing parameters.