Abstract: WC-Co coating was cladded on the surface of H13 by YLR-2000 continuous fiber laser, and the influence of power, scanning speed and powder feeding amount on the forming quality of the coating was analyzed by orthogonal experiment to determine the best parameters. The morphology of the coating structure was analyzed by optical microscope and SEM. The hardness of the coating was tested using Vickers hardness tester. The results indicate that the laser power has the greatest effect on the melt width and height of the coating, while the scanning speed and powder feed rate have little effect on the melt width and melt height of the coating. The optimized process parameters as follows: laser power 600 W, scanning speed 8 mm/s, powder feed rate 6 g/min. The top microstructure of the H13 alloy base after laser 3D printing is mainly mesh branch crystal, the bottom is mainly columnar branch crystal. The microstructure of the WC-Co melting coating mainly consists of cellular crystals and equiaxed dendrites. A good metallurgical bond is formed between the coating and the base layer. The hardness of cross section of the composite coating decreases gradually from the coating to the base layer. The average microhardness of the base layer is 464.21 HV0.1, and the average microhardness of the coating is 1218.11 HV0.1,which is 2.62 times of that of the base layer.