Abstract: The carbon and oxygen contamination on Ti surface strongly influences the hydrogen absorption and desorption capability, and even can completely passivate the surface. The effect of C and O on Ti films is investigated by high energy nonrutherford backscattering and elastic recoil detection. The experiment results show that the concentration gradient in the region of about 300 nm near the surface is very large due to the joint contamination of about 1 26×10 16 cm -2 C and 2 5×10 16 cm -2 O, and thermal releasing temperature is also increased greatly. Thin Ni film coated on the Ti film may considerably improve the hydrogen absorption and desorption capability.