In this study, the Er3+:YAlO3 as up-conversion luminescence agent, which can transfer the visible light part in the sonoluminescence to ultraviolet light, was synthesized by nitrate-citrate acid and sol-gel method. And then the Er3+:YAlO3/TiO2-Fe2O3 composite as a sonocatalyst was prepared by ultrasonic dispersion and liquids boil method. The prepared Er3+:YAlO3/TiO2-Fe2O3 composite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The sonocatalytic activity of Er3+:YAlO3/TiO2-Fe2O3 composite was examined through the degradation of organic dye in aqueous solution under ultrasonic irradiation. The influences of key preparation conditions such as Ti/Fe molar ratio, heat-treated temperature and heat-treated time on the sonocatalytic activity of Er3+:YAlO3/TiO2-Fe2O3 composites were studied. The results indicated that the Er3+:YAlO3/TiO2-Fe2O3 composite with 1:1 molar ratio of Ti/Fe heat-treated at 500 degrees C for 20 min displays the highest sonocatalytic performance in the degradation of Acid Red B. For the degradation of other organic dyes, the Er3+:YAlO3/TiO2-Fe2O3 composite also demonstrates a good sonocatalytic activity. (C) 2011 Elsevier BM. All rights reserved.