Abstract: The chemical nature of depleted uranium is very active and prone to oxidation corrosion in nature environment. In this study, CrN_x film was prepared on the surface of depleted uranium by unbalance magnetron sputtering ion plating to improve its corrosion resistance. The Xray photoelectron spectroscopy (XPS) was used to characterize the chemical state and depth profiles of Cr, N and O elements. XRD was employed to examine the phase structure of CrN_x film. The corrosion behavior of the samples was measured by using polarization curves (E/I). The results show that CrN_x film prepared by unbalance magnetron sputtering has good density and corrosion resistance. The phase composition of CrN_x films is composed with Cr, CrN and Cr₂N when the N₂ flow is lower. After a layer of CrN_x is deposited on the surface of uranium, the corrosion potential increases about 465 mV, while the corrosion current density decreases significantly. It is indicated that the corrosion resistance of depleted uranium is effectively improved after depositing CrN_x thin film by unbalance magnetron sputtering.