Abstract: To control the shape and distribution of hard phase,longitudinal magnetic field was applied during plasma hardfacing of Fe5 alloy.The hardness,wearing,microstructure and X-ray diffraction analysis of the hardfacing layer were tested as well as the structure and property of the handfacing layer of the powder.The results showed that the layer had higher hardness and better wearing with magnetic field than the layer formed without magnetic field.The properties of hardfacing layer were optimum when the magnetic field current was 3A and the microstructures of alloy hardfacing layer obtained ideal hard phase such as Cr₇C₃,CrB ect and solid solution α and γ were refined sufficiently.