Abstract:MoFeCrTiWSix (x=0, 0.2, 0.4, 0.6, 0.8, 1.0) multi-principal element alloy coatings were fabricated on Q235 steel by laser cladding. The effect of silicon on the microstructure, phases, microhardness and high-temperature oxidation resistance were investigated systematically by X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester etc. The results show that, the phase of laser cladding MoFeCrTiW multi-principal element alloy coating is single BCC structure and its microstructure is equiaxed grains. The main phase is still BCC structure after adding different content of silicon into coating. When the content of silicon is no less than 0.4 moles, there exits small intermetallic compound in the coatings, the microstructures of coatings are composed of proeutectic BCC phase and eutectic structure of BCC phase and Cr5Fe50Mo8.9Si5.2Ti20.4 phase. With the content of silicon increasing, the morphology of proeutectic phase changes from cystiform-dendritic to columnar dendrites and equiaxed dendrites, while the content of eutectic structure is increased gradually. From the surface to bonding zone of coatings, the distribution of the mixing entropy changes from high entropy to medium entropy. With the addition of silicon, the microhardness and high-temperature oxidation at 900℃ of coatings are increased. When x is 1.0 mole, both the microhardness and the high-temperature oxidation resistance are the highest.