Rare earth ions doped TiO2 is supposed to convert near-infrared (NIR) light into visible light that can be absorbed by the visible-light-driven photocatalyst. In this work, a new (Yb3+, Er3+) co-doped TiO2/Ag3PO4 hybrid photocatalyst with up-conversion function had been prepared. The as-prepared composite exhibited much more enhanced visible-light photocatalytic activity towards degradation of phenol than that of pure Ag3PO4 and TiO2/Ag3PO4, which can be ascribed to the extended light absorption range and efficient charge separation property. The possible intermediate products generated during the photodegradation of phenol were also investigated. A possible photodegradation pathway for phenol and a mechanism for the enhanced photocatalytic activity were proposed. This work may provide a new insight into the preparation of hybrid photocatalyst consisting of up-conversion materials and visible-light-driven photocatalysts for the applications in degradation of harmful organic compounds under sunlight irradiation.