Abstract: In order to analyze effect of laser power on microstructure and properties of Co-based gradient wear-resistant coatings, alloy powders of St6, St12B and Co47+WC (mass fraction of 0.05) were claded on the surface of 20CrMnMo steel. Co-based gradient wear-resistant coatings with the thickness of about 2.4mm were prepared to do microstructure analysis, microhardness test, friction and wear test. The results show that there is no crack on the surface of the coatings under different laser powers. The morphology of the crystals in each coating is similar:dense equiaxed grains in the surface layer, large columnar crystals in the transition layer, and plane and dendrites in the bottom layer. The unmelted WC particles are found in the wear-resistant layer at 600W. The hard phase of CoW₂B₂ is found in the wear-resistant layer at 800W. From the study about the properties of the coatings, the higher the laser power, the better the microhardness and wear resistance of the coatings in the range of 600W to 800W. When laser power is 800W, microhardness of the wear-resistant layer is 730HV_0.1, and wear resistance of the coating is 300% higher than that of the matrix. The results of this study provide a reference for the preparation of Co-based gradient wear-resistant coatings by laser cladding.