Abstract: TiO2 photocatalyst has some disadvantages, such as wider band gap, high electron-hole recombination rate, etc. Therefore, a lot of research work focused on the modification of TiO2 photocatalyst has been carried out at home and aboard. Some modification methods of TiO2 photocatalyst, e.g. noble metal deposition, element doping (metal ion doping, non-metal doping, and co-doping), compound semiconductor, photosensitization, and surface acidification, as well as their mechanisms are summarized. Among them, the response wavelength of TiO2 shows a red-shift after non-metal doping or co-doping, at the meanwhile, UV response of TiO2 is preserved, therefore, the superimposition of good process effect is realized. The future direction of photocatalytic study is looked into, giving consideration to the production cast, keeping the stability of TiO2 in complex environment, and increasing recovery rate of TiO2.