In this work, the Er3+:YAlO3/Fe-doped TiO2 composite, a high efficient TiO2-based photocatalyst, was synthesized by ultrasonic dispersion and liquid boil methods. Among which, the Er3+:YAlO3 is a kind of upconversion luminescence agent, which was prepared by nitrate-citric acid method. It can emit ultraviolet light under visible light excitation. The Er3+:YAlO3/Fe-doped TiO2 composite was characterized by X-ray diffraction and UV-vis spectral techniques. The degradation of Acid Red B dye was used to evaluate the photocatalytic activity of the Er3+:YAlO3/Fe-doped TiO2 composite under solar light irradiation. It was found that the photocatalytic activity of Er3+:YAlO3/Fe-doped TiO2 composite was much higher than that for the similar system with only Fe-doped TiO2. And the influencing factors, such as Er3+:YAlO3 content, irradiation time, initial concentration of Acid Red B, addition amount of Er3+:YAlO3/Fe-doped TiO2 and NaCl, on the photocatalytic degradation were also investigated. The Er3+:YAlO3 as upconversion luminescence agent can elevate the photocatalytic activity of Fe-doped TiO2 powder. Moreover, the Fe2+ ion can restrain the recombination of photogenerated electrons and holes. Thus, this Er3+:YAlO3/Fe-doped TiO2 composite is a useful material for the detoxification of wastewater because it can efficiently utilize solar light by converting visible light into ultraviolet light.