The coadsorbed structures of Na and NO on perfect TiO2(110) surface were optimized and the DOS of the stable model of Na adsorption was performed. based on DFT/B3LYP method. The optimization result indicates that the Na atom prefer to bind on the 'adjacent' site and the NO adsorbs on Na/TiO2(110) by its O atom vertically located at Ti(5f). The Na adsorption on TiO2(110) perfect surface leads to produce a new surface state which is similar to that of TiO2(110) oxygen defect surface, but the components and active positions of both the surface states are different. The results are in good agreement with the experiments. (C) 2004 Elsevier B.V. All rights reserved.