Carbon and oxygen contamination on the Ti surface strongly influences hydrogen absorption and desorption, and it can even passivate the surface completely. The effect of C and O on the hydrogen absorption and thermal release on Ti films was investigated by using high-energy non-Rutherford backscattering and elastic recoil detection techniques. The experimental 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 X 10(16) atoms/cm(2) of C and 2.5 x 1016 atoms/cm(2) of O; also, the thermal releasing temperature increased greatly. A thin Ni film coated on the Ti film may considerably reduce the contamination of gaseous impurities, in particular C, and prevents further oxidation and improve the absorption and desorption of hydrogen.