Vanadium-doped microarc oxidation (MAO) films were prepared on a magnesium substrate by adding a small quantity of ammonium metavanadate into MAO solutions to control the electrochemical and optical properties of the films. The results indicate that the doping content of vanadium in the film is about 8.5at%, and some of vanadium forms V2O3. The porous structures of doped and undoped films are notably different, but similar thickness and hardness are demonstrated. The polarization curve test reveals that the corrosion potential of the doped film obviously rises, but the corrosion current remarkably decreases, whose values change from –1.208 V and 0.825×10-3 A/cm2 without doping to –0.037 V and 0.3837×10-4?A/cm2 with doping, respectively. The UV-Vis spectra indicate that vanadium-doping can weaken the reflectance, and a significant decrease is especially observed in the range of visible light