The work aims to improve the forming quality of the cladding coating by optimizing the process parameters in plasma cladding of cobalt-based alloy. The multitrack Co-based alloy wear-resistant coatings coated on Q235 steel were taken as the research object to carry out the orthogonal experiment. The microstructure and phase composition of coatings in different regions were analyzed by MIRA3X-MHX scanning electron microscope, and the surface smoothness and the microhardness of cross section of the coatings were measured and analyzed by KEYENCE VHX-5000 ultra-depth-of-field microscope and HXD-1000TMC/LCD Vickers microhardness tester. The comprehensive effects of working current, scanning speed and powder feeding speed on the surface smoothness and microhardness of the cladding layer were investigated by grey correlation analysis and range analysis, and then the optimum technological parameters were obtained. The working current had the most significant effect on the forming quality of cladding layer, followed by scanning speed and powder feeding speed. The fluctuation of longitudinal microhardness in cross section of each cladding layer was roughly the same, the maximum microhardness appeared about 0.4 mm away from the upper surface layer, and the average microhardness of the cladding layer was more than 3 times that of the matrix material. The distribution of microstructure in the upper part of the cladding layer was uniform and dense. With the decrease of the distance between the cladding layer and the substrate, the dilution rate of the cladding layer increased and the microhardness decreased gradually. Under the combination of working current of 95 A, scanning speed of 90 mm/min and powder feeding speed of 12 r/min, the cladding layer was well combined with the substrate without gas holes and clearances, the average microhardness of cross section was higher and the surface of the cladding layer was more flat. The surface properties of the cladding layer are effectively improved by optimizing the process parameters of plasma cladding forming quality. The results can provide a reference for the study on the plasma cladding technology applied to the wear resistance of wearable workpieces.