Abstract: As a new kind of photocatalytic material, TiO₂ has the characteristics of non-toxicity, mild reaction conditions and stable chemical properties, which has attracted much attention. At present, how to prepare efficient nano TiO₂ has become a hot topic in material research. This paper includes the review of advantages of TiO₂ photocatalyst and its limitations in application. A detailed discussion on the photocatalytic mechanism of TiO₂, the four methods including metal doping, co-doping, noble metal deposition and semiconductor composite, and the research progress of photocatalytic performance at home and abroad were analysed.