An alumina coating with a thickness of 65μm was prepared on depleted uranium surface by cathodic microarc desposition in 1mol/L Al(NO₃)₃.9H₂O ethanol solution. The morphology, composition and phase constituent of alumina coating were analyzed by SEM, XRDand EDS. The corrosion resistance were determined by electrochemical integrated test system. The results show that the coating, which is composed of α-Al₂O₃and γ- Al₂O_3, remain a good adhesion to depleted uranium substrate. The coating contains a little uranium element, which confirms that depleted uranium substrate near the coating /uranium also takes part in the sintering process of coating under cathodic microarc discharge. The coating reduce the depleted corrosion current by two orders-of-magnitude, which shows the good corrosion resistance.