Abstract: The high chromium iron based alloy coating was fabricated on the surface of medium carbon steel by plasma cladding using the powders by precursor carbonization-composition process.Microstructure, hardness distribution and cavitation erosion resistance were observed and measured by OM, X-ray diffraction, SEM, microhardness tester and ultrasonic oscillation magnetostriction strain gauge.The process of cavitation erosion was analyzed.The results show that the coating has high microhardness and good cavitation erosion resistance.The cumulative mass loss is only 49.8% as the one of 0Cr13Ni6Mo steel after 44 hours cavitation erosion.The excellent cavitation erosion resistance of the coaring is due to the following factors:the grain boundary of hard phase hinders plastic deformation of phase γ and the stress induces the phase γ changing to martensite structure.