Copyright © 2014 American Scientific Publishers All rights reserved. The Fe3O4/SiO2/CeO2core-shell magnetic has been successfully synthesized by three steps of hydrothermal, sonochemical and homogeneous precipitation by coating CeO2nanoparticles onto Fe3O4/SiO2magnetic core. The prepared samples were characterized by X-ray diffraction (XRD), Field-emission scanning electron microscopy (FESEM) connected with energy dispersive X-ray analysis system (EDS), high resolution transmission electron microscopy (HRTEM), Nitrogen adsorption-desorption analyses (BET), and vibrating sample magnetometer (VSM). The photocatalytic activities for Fe3O4/SiO2/CeO2core-shell magnetic under UV and visible lights were measured by determining the degradation rate of formic and oxalic acid in spiral reactor for 120 min. The amounts of CO2generated during the process were compared between the magnetic catalyst and bare CeO2. After the finished photocatalytic degradation, the magnetic catalyst was recovered by external magnetic field at the end of each experiment. The results showed that the photocatalytic activity of Fe3O4/SiO2/CeO2core-shell magnetic had higher than that of bare CeO2and was found to be constant for three cycles of the recycled use.