Mono-hydrogenation effect on the properties of fullerenes C60 and C70 was investigated by the density functional theory (B3LYP/6-311G(d, p)). One isomer of C60H and five isomers of C70H were examined, comparing with C60 and C70. Energies of fullerene mono-hydrides (FMH) are smaller than the summation of energy of the fullerene and that of hydrogen atom. Dipole moments of cationic FMH (+) are much larger than those of neutral FMH radicals (0). Mono-hydrogenation decreases frontier energy gap (Eg) and excitation energy (Eex) by about 0.9eV. The hyperfine coupling constant (aH), spin density (H, C), and reorganization energy () are strongly dependent on the addition position of hydrogen atom.