[en] The corrosion-resistance in humid air at 70 degree C and 40 degree C of uranium treated with CO has been studied using weight gain method. The results show that the oxidation-resistance of treated uranium in moist air has not been enhanced obviously at 70 degree C, but has been improved clearly at 40 degree C. Increasing dose of CO in the experimental range gives the better results. The composition of surface layer of uranium and treated uranium have been analyzed respectively by Auger Electron Spectroscopy (AES). The analysis indicates that there is a rich-carbon layer formed in the surface layer after uranium has been treated with CO, and this rich-carbon layer is probably important to enhance the corrosion-resistance of uranium