To improve the wear resistance of AZ31B magnesium alloy, laser surface cladding with Al-Si and Al2O3-TiO2 mixture powders (in the mass fraction ratio of 61) is investigated by a CO2 laser. The microstructure, phase analyses and wear behavior of AZ31B modified is studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and wear methods. The XRD pattern shows that the coating is composed of Mg17Al12, Al3Mg2, Mg2Si, Al2O3, TiO2, etc. The average microhardness of the surface layer is significantly improved to 245 HV0.05, as 4 times higher of that of the AZ31B substrate. The coating′s excellent wear resistance is due to the recombination of embedding of ceramic particles and intermetallic compounds. The worn mass of the composite coating decreases by 81.4% compared with that of the substrate.