Abstract: In view of surface problems such as wear and corrosion caused by the failure of H13 die steel, nickel-based silicon carbide powder was used to optimize the parameters of the repair layer of H13 die steel. In order to explore the effect of laser parameters on the repair layer in laser cladding, laser cladding experiments were carried out using different laser currents and defocus amounts as optimized process parameters. It was found that changing the size of the laser current and the amount of defocusing had different degrees of influence on the cladding size, microstructure and mechanical properties of the repair layer. The geometric dilution rate of the cladding layer increases as the laser current increases, and the grain size of the cladding layer becomes coarse; The geometric dilution rate of the cladding layer decreases as the amount of defocus increases, and the grain size of the cladding layer becomes finer. The optimized results obtained through the analysis of metallographic microscope, SEM and micro hardness tester showed that the laser current is 115A, the defocus amount is 51mm, and the microhardness value of the cladding layer reaches the highest value, which is about 2.6 times the hardness of the substrate. The above research results provide theoretical and technical basis for improving the quality of the laser cladding repair layer on the failure surface of the mold.