Abstract: The solid boronizing tests of Mg/Al multilayer composite plate under two conditions were compared.The X-ray diffractometer (XRD)and scanning electron microscopy (SEM) were used to analyze the phase composition and the microstructure of the Mg/Al multilayer composite plate after boronizing.The hardness of the infiltrated layer was tested using microhardness tester.Electrochemical polarization curves were tested on the substrate and the surface layer.The results show that the infiltration layer obtained at 630 ℃for 10 h is better than the infiltration layer obtained at 600 ℃for 10 h.The infiltration layer is mainly composed of phases such as MgAlBO₄, B₂O₃ and AlB₁₂, and the thickness is about 20 μm.The corrosion resistance and hardness of the samples are significantly improved, and the microhardness of the infiltrated layer is as high as 278 HV.