Abstract: Laser cladding Ni-based WC composite coating was fabricated on the surface of Q235 steel by using 6kW fiber laser. By using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and micro-hardness tester, we investigated the morphology, composition, and micro-hardness of composite coating in different laser power. The results show that WC particles partially dissolve and react with other elements to form eutectics, which exist in the shape of block, strip and grain. The cladding height, penetration and dilution of laser cladding coating increased gradually with the increase of laser power. Moreover, the average hardness of the coating increased first and then decreased with the increase of laser power. When the laser power was 2500W, cladding coating could get the highest hardness, which could reach 5 times of the matrix hardness.