Abstract: For studying the influence of plasma gas flow rate on the microstructure and mechanical properties of Fe-Cr-B-C alloy cladding layer, the Fe-Cr-B-C alloy cladding layer was prepared on the surface of Q235 steel plate by plasma cladding technology. The microstructure and phase of the cladding layer were studied by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS）, and the hardness and wear resistance of the coating were analyzed by microhardness tester and friction and wear tester. The results show that the main phase of the cladding layer prepared by plasma cladding is martensite, Fe₃C, Cr₂₃C₆, Fe₂B, Cr₂B, Fe₂C, Fe₇C₃and a small amount of oxides. Boron-carbides are distributed in the matrix as a net shape, and the content decreases with the increase of plasma gas flow rate. With the increase of plasma gas flow rate, the hardness of the cladding layer gradually decreases, and the wear amount decreases first and then increases. When the plasma gas flow rate is 2 L/min, the wear resistance of the cladding layer is best, and the wear amount is 0.0257 mm~3, which is 6% of Q235. The wear mechanism of Fe-Cr-B-C cladding layer is dominated by adhesive wear and abrasive micro-cutting.