The laser surface cladding of AZ91D magnesium alloy with Ni-Cr-B-Si+WC powders has been investigated. Laser surface cladding was conducted using a continuous wave CO₂ laser. As a result,a good metallurgical bond interface was obtained between Mg alloy substrate and coating. The microstructure and phase analysis of the coating were carried out by scanning electron microscope (SEM) and X-ray diffraction (XRD). The hardness and the corrosion properties of the coating were also measured. The experimental results show that the cladding layer is composed of AlNi3,Al3Ni2,Ni(Cr2O4) and different kinds of carbide. The cracks and porosity of coating are decreased with the join of 25% WC particles. The hardness of the cladding layer is significantly improved by 9.4 times higher than that of the AZ91D substrate,and the modulus is about twice higher than that of the substrate. The corrosion resistance of the laser modified samples is considerably improved as compared to the substrate.