The pristine mesoporous titanium dioxide (M-TiO2) and the doped mesoporous titanium dioxide (doped M-TiOD were successfully prepared as photocatalysts via a sol-gel method. Surfactant of hexadecyltrimethyl ammoniumbromide (CTAB) was used as a template. Those mesoporous photocatalysts (M-TiO2, and various doped M-TiO2) were characterized by thermogravimetric analysis (TGA), X-ray diffractometer, small angle X-ray spectrometer (SAXS), transmission electron microscopy (TEM), specific surface area analysis (BET), and UV-visible spectrometer. The performances of the synthesized photocatalyst were measured by the photodecomposition rate of methyl orange using an UV irradiating light of 365 nm. The performances for the synthesized mesoporous titanium dioxides (the M-TiO2, and the doped M-TiO2) were much better than that for the non-mesoporous titanium dioxide (P-25). The doped M-TiO2, in turn, is better than pristine M-TiO2. Doping wolfram in the M-TiO2 is able to shift the excitation source from the ultraviolet to the visible light. There exists an optimum amount of dopant in preparing an active photocatalyst. In this study, the M-TiO2 doped with 0.5 mole% is better than that doped with 2.0 mole%, rather than preferring the larger amount doped. (C) 2007 Elsevier B.V. All rights reserved.