Abstract: The WC-12Co was deposited on the surface of FS438 steel with WC-12Co as the electrode and argon gas as the protective gas. Voltage, capacitance, frequency and deposition time were selected as processing parameters, orthogonal experiment method was used to carry out experiments, and range analysis of experimental results were obtained. The coating thickness and surface roughness of the orthogonal experiment results were processed using a dimensionless method, and their correlation coefficients and correlation values were calculated, and then the calculation results were analyzed with gray correlation, and finally the optimization of multi-index process parameters was realized. The surface morphology of the deposited layer prepared under the optimized process parameters was analyzed by optical microscope. The results show that the processing parameters that have the greatest influence on the thickness and surface roughness of the WC-12Co coating are voltage and capacitance. When the process parameters are voltage 50 V, capacitance 120 μF, frequency 360 Hz, and deposition time 4 min/cm², the thickness of the prepared WC-12Co coating is 55.125 μm, and the surface roughness is 5.073 μm, the surface of the coating is denser and has a better finish. The comprehensive performance of the thickness and surface roughness of the coating is relatively good.