Abstract: The parameters of plasma cladding technology (PCT)were optimized by orthogonal tests, and the CoCrFeMnNi high entropy alloy coating was prepared by PCT on Q235 steel substrate.The microstructure and properties of cladding layer after optimization were analyzed by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectroscopy (EDS) and microhardness tester.The results show that the significance influence of plasma cladding process parameters on the dilution ratio of cladding layer is in turn with the cladding speed, arc current and feeding gas flow, but which on the microhardness of cladding layer is in turn with the arc current, cladding speed and feeding gas flow.The optimal parameter combination obtained by the polar difference and macromorphology of cladding layer is arc current of 70 A, cladding speed of 7 mm/s, feeding gas of 8 L/s.Under these conditions, the cladding layer is crack-free, the main elements are uniformly distributed in the cladding layer surface, and the cladding layer is only composed of FCC structure phase as the type of Ni.The dilution ratio of the cladding layer is about 17.86%.The hardness distribution on the cladding layer surface is relatively uniform, while the microhardness of the cross section varies with gradient under the influence of microstructure.