Abstract: The combination of the process of TiO2 photocatalytic oxidation with microwave，ultrasound，electric field，magnetic field，thermal catalysis，nonthermal plasma and thermal catalysis is a new effective method to improve photocatalytic activity of TiO2. In this paper，the mechanisms of synergistic effect of external field assisted catalysis are discussed，and the research development on degradation of organic compounds is summarized. Finally，application prospects and the research directions in the field of environmental protection are presented.