The purpose of this paper is to study the optimal process parameters of laser cladding of 431CO-M2 alloy powder on the surface of 3Cr14 stainless steel. Based on the orthogonal experimental design, the method of range analysis was adopted to study the influence of laser power, cladding speed, powder feeding speed and protective gas size on the molding quality of cladding layer by taking dilution rate, forming coefficient and macroscopic hardness as evaluation indexes, so as to select the optimal cladding process parameters. The degree of influence on the dilution rate and forming coefficient is laser power, cladding speed, powder feeding speed, and protective gas size in descending order, The degree of influence on macroscopic hardness was laser power, powder feeding speed, cladding speed and protective gas size in order from large to small. The optimal process parameters are laser power 1 100 W, scanning speed 5 mm/s, powder feeding speed 26 g/min, protection size 0.1 MPa, spot diameter 4mm, carrying capacity 13 L/min, defocusing capacity 14 mm. Under the optimal process parameters, the surface of the cladding layer is continuous and smooth, and is closely combined with the substrate. The average microhardness of the cladding layer is 684.5 HV0.2, which is about 2.7 times of the average microhardness of the matrix, significantly increasing the hardness of the matrix.