A series of Ti1-xMoxO2-yNy samples were prepared by using sol-gel method and characterized by X-ray diffraction, transmission electron microscopy and UV-vis absorption spectroscopy. All Ti1-xMoxO2-yNy samples are anatase phase. It is found that Mo, N mono-doping can increase visible light absorption, while (Mo + N) co-doping can greatly enhance absorption in whole visible region. Results of our first-principles band structure calculations reveal that (Mo + N)-doping, especially passivated co-doping can increase the up-limit of dopant concentration and create more impurity bands in the band gap of TiO2, which leads to a greatly increase of its visible-light absorption without a decrease of its redox potential. It reveals that (Mo + N) co-doped TiO2 is promising for a photocatalyst with high photocalystic activity under visible light. (C) 2011 Elsevier B.V. All rights reserved.