Abstract: The synthetic methods of nano-titanium dioxide are reviewed, which includes prepare methods of gas phase and liquid phase. The surface modification technologies of nano-TiO₂ particles, including inorganic coating and organic modification, are summarized. The physico-chemical properties and application fields of nano-TiO₂ are introduced in brief. The research advance of nano-TiO₂ in functional modification of plastics is reviewed in particularly, such as aging resistance composites, antibacterial composites and so on. Furthermore, the action mechanisms of nano TiO₂ in aging resistance and antibacterial are emphatically discussed.