Oxide semiconductors are widely used in the photocatalytic fields and introducing oxygen vacancies is an effective strategy to reduce the band gap, and consequently, improve their photocatalytic efficiency. However, oxygen vacancies in bulk often act as the recombination centers of electron-hole pairs, which would accelerate the recombination of electron-hole pairs and reduce carrier migration rate. Therefore, for achieving excellent photocatalytic performance in oxide photocatalysts, taking good advantage of oxide vacancies is very crucial. In this paper, we propose a strategy of electric field treatment and apply it in the TiO2 film with oxygen vacancies to promote the photocatalytic efficiency. After treated by an electric field, conductive channels consisting of oxygen vacancies are formed in TiO2 film, which makes the resistance greatly decreased by almost 6Ă103 times. In the photocatalytic CO2 reduction reaction, the yield of CO in the electric-field-treated TiO2 film can reach up to 1.729 mmol·gcat-1·h-1, which is one of the best performance among the reported TiO2-based catalysts. This work provides an effective and feasible way for enhancing photocatalytic activity through electric field and this method is promising to be widely used in the field of catalysis.