Abstract: Decomposed CO2 gas is implanted to uranium at different energy, beam current and temperature. The Auger electron spectromy (AES) and globe angle X-ray diffraction (GAXRD) are applied to analyze the element distribution and phase structure of modified layers. The induction time is investigated on implanted sample by uranium-hydrogen reaction at 100 ℃ and 0. 2 MPa conditions. The surface micrography is investigated by scanning electron spectromy (SEM) before and after uranium-hydrogen reaction. The results show that the modified layer implanted with oxygen and carbon ions consists of UO2 and C at the condition of 35 kV/8-9 mA/3 h, UO2 and small UC at the conditions of 65 kV/8~9 mA/3 h and 3 kV/80 mA/3 h. The induction of the implanted sample increases significantly, because the UO2 and UC modified layers retard to the production nuclei and growth of hydride. The depleted uranium has macros flake on sur- face, but the implanted samples have isloated spots after uranium react with hydrogen.