A novel nanometer-sized magnetic photocatalyst (TiO /SiO /Fe O ) to be separated and recovered is prepared. The photoactive TiO is deposited on the surface of magnetic particles using the sol-gel coating technique. These samples are characterized by IR, XRD and TEM. Using the organic sewage as a decomposition substance, the catalysts show that the photocatalytic activity is improved after using the intermediate coating SiO , and the photocatalyst makes organic sewage decomposite quick and keep the decomposition efficiency up to 90% after five times. Moreover, degradation ratios of the mixed catalysts have 99% to the saline sewage and 86.8% to the phenol sewage. It has a good degradation effect to the dye-based sewage with easy recycling by the magnet.