Al Cu and Al Si powders were prepared on the surface of AZ31B magnesium alloy by a method of combining Laser cladding and friction stir processing. The microstructure and phase analyses of the modified layer were studied by scanning electron microscopy and X-ray diffraction measurement. Meanwhile, The microhardness and corrosion resistance of the modified layer were investigated in detail. The composite modified layers with Al Cu and Al Si powders are compose of β-Al₁₂Mg₁₇, AlCu₄, AlMg and Mg₂Si, AlMg, β-Al₁₂Mg₁₇, respectively. Both modified layer showed very good bonding with the magnesium alloy substrate. The microhardness and corrosion resistance of the modified layer are higher than that of substrate. Compared with the matrix, the maximum microhardness (296 HV) of the modified layer with Al Si powders increased by 385.3%, and the maximum self-corrosion potential (-0.975 V) with Al Cu powders increased by 37.4%.