Increased the concentration of the carrier, make the electronic, cavitation number, has the stronger capture in TiO2 on the surface of the solution components (water, oxygen and organic matter). : the mechanism of nanometer titanium dioxide with large specific surface area, surface atom number, surface energy and surface tension with the increase of particle size of drop sharply, small size effect, surface effect, quantum size effect and macroscopic quantum tunneling effect leads to the heat, magnetic nanoparticles, light, sensitive properties and surface stability of different conventional particles. Because of the characteristic of the electronic structure of TiO2 has, to make it by light generated when chemical active sex very strong superoxide anion free radicals and hydrogen and oxygen free radicals, attack organic, to achieve the effect of degradation of organic pollutants. When encountered bacteria, attack bacteria cells directly, causing bacteria of organic matter degradation in cells, to kill bacteria, and decomposition. Nanometer titanium dioxide can not only affect fertility, bacteria and can destroy bacteria cell membrane structure, achieve complete degradation bacteria, prevent secondary pollution caused by endotoxin, nano titanium dioxide belongs to non dissolution material,