The structure and properties of nano TiO 2 and its polymeric composites were studied in this paper. The polymeic materials added nano TiO 2 with anti ultraviolet,anti aging and antimicrobial functions were discussed mainly. The experimenal results of 1000 h exposure in the extra ordinary baneful environment were shown. A sufficiency of experimental datal demonstrated that nano TiO 2 photocatalysts possessed anti bacterial function and obviously increas the toughness for plastic, but the effect on the strength for plastic was less. The nano TiO 2 photocatalyst had both bactericidal activity and decomposing activity for endotoxin. The destruction function of nano TiO 2 for bacterials was compared to ordinary silver and copper antiseptic.