TiO2 is of good performance, such as chemical stability, high photocatalysis activity, and so on. The photo-induced super hydrophilicity of TiO2 is a research focus lately. The photocatalysis mechanism of TiO2 was presented in this paper. The effect of crystal configuration, external impurities, light and its intensity, semi-conductor dual composite on the photo-induced super hydrophilicity of TiO2 was discussed. The industrial applications of TiO2 were introduced.