Iodine-doped mesoporous TiO2 (I/TiO2) was prepared by hydrothermal method, using tetrabutyl titanate as precursor, potassium iodate as iodine sources. The as-prepared I/TiO2 catalysts were characterized by UV-vis, XRD, TEM, BET, TG/DTA, XPS and photoluminescence (PL) spectroscopy. Production of (OH)-O-center dot radicals on the I/TiO2 surface was detected by the PL technique using terephthalic acid as a probe molecule. The effects of hydrothermal reaction temperature, calcination temperature and iodine doping content on the structure and properties of the catalysts were investigated. The results showed that iodine-doped TiO2 calcinated at 300 degrees C have good anatase crystal. The optimal hydrothermal conditions have been determined to be that reaction temperature 120 degrees C, calcinated temperature 300 degrees C and added 1.16 mmol iodine dopants. The average particle size of I/TiO2 synthesized under optimal condition (I-3 sample) is about 3.9 nm. The I-3 photocatalyst contains 100% anatase crystalline phase of TiO2. BET specific surface area of I-3 sample is 184.8 m(2) g(-1) and is 3.67 times that of pure TiO2 (50.37 m(2) g(-1)). Iodine in I/TiO2 catalyst mainly exists in the form of I-2, and photoactivity of I/TiO2 catalyst in visible light comes from photosensitize of I-2.I/TiO2 catalysis shows very high efficiency for the degradation of phenol under visible light. (C) 2010 Elsevier B.V. All rights reserved.