Abstract: The composite of Sm-doped TiO₂ nanoparticles loaded onto carbon nanofibers (SmTiO₂/CNFs ) was prepared by electrospinning technique and thermal processes. The samples were characterized by SEM, EDX, TEM, FTIR and XRD.The effect of Sm-doping on the photocatalytic activity of the SmTiO₂/CNFs composite was investigated by the photocatalytic degradation of methyl orange aqueous solution under UV irradiation.The results show that the CNFs are loaded with about 20% mass fraction of Sm---doped anatase TiO₂ nanoparticles. In comparison with the undoped sample (TiO₂/CNFs), the photocatalytic activity of the SmTiO₂/CNFs increases by about 37%.