The effect of α-Al2O3 nano-additives on anodic oxide film-forming and film performance was studied. The morphology and phase compositions of the anodic oxide films were analyzed by scanning electronic microscope (SEM) and X-ray diffraction (XRD). The corrosion resistance of the anodic films with nano-Al2O3 was investigated by immersion test and potentiodynamic polarization technique. The results show that anodic oxide films mainly consists of Mg, Al12Mg17, γ-Al2O3, a little of Si and α-Al2O3. The corrosion resistance property of magnesium alloy can be improved with the addition of α-Al2O3 nano-additives.