In this work structural defects were created in P25-TiO2 nanoparticles by using hydrogen DC plasma treatment in different temperatures and exposure times. X-Ray diffraction measurements show that the structure of TiO2 remains unchanged after hydrogenation. Diffuse reflectance spectroscopy measurements demonstrated that the band gap of TiO2 was not changed considerably by the hydrogenation. However, by applying the hydrogen plasma for 40 min at a temperature of 350 ° C, photocatalytic activity of TiO2 nanoparticles enhances. No more change was observed in the photocatalytic activity of the samples with plasma exposure time more than 40 min. Photoluminescence analysis shows the sample prepared at 350 ° C has a large amount of defects created by the plasma treatment. It seems both, structural defects and hydrogen doping in the samples are important for more efficient photocatalytic behavior of TiO2 nanoparticles. PACS: 82. 45. Jn, 61. 46.-w, 61. 72.-y, 78. 55.-m.