Cold rolls made of Cr12MoV are subjected to fatigue stress and thermal cycling during the rolling process, resulting in defects in the form of spalling and cracks on the roll body. In order to solve this problem, a broad -beam laser melting equipment is used to prepare an alloy coating on the surface of Cr12MoV steel by using Cr12MoV alloy as the cladding powder. Taking the laser power, scanning speed, powder feed rate and overlap ratio as variables and the surface roughness and microhardness of the cladding layer as the optimized target parameters, orthogonal tests are carried out and the optimized combination of the variable parameters is obtained by using the methods of range analysis and variance analysis to analyze the target parameters. The results show that the optimum variable parameters combination is laser power 2 000 W, scanning speed 10 mm/s, powder feed rate 10 g/min and overlap ratio 45%. The cladding test is conducted under this variables combination, the obtained surface roughness is 16 μm, and the average microhardness of the coating is 677 HV which reaches 96% of the value of the base material, and the cladding layer has a uniform microstructure without defects such as porosity and cracks.