A composite photocatalyst (Ce-TiO 2 /Fe 3 O 4 ) with cerium doped anatase titanium dioxide (Ce-TiO 2 ) shell and a magnetite core was prepared by coating photoactive Ce-TiO 2 onto a magnetic Fe 3 O 4 core through the hydrolysis of tetrabutyltitanate in water/oil (w/o) microemulsion with precursors of ammonium ceric nitrate and tetrabutyltitanate in the presence of Fe 3 O 4 nanoparticles. The morphological, structural and optical properties of as-prepared samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV–vis diffusive reflectance spectroscopy (UV–vis DRS). The effect of cerium content on the photocatalytic activity was studied, and the result reveals that 0.15mol% Ce-TiO 2 /Fe 3 O 4 exhibits highest photoactivity. The cerium doping causes absorption spectra of Ce-TiO 2 /Fe 3 O 4 to shift to the visible region. The photocatalytic activity of the prepared photocatalyst under UV and visible light was estimated by measuring the degradation rate of phenol (50mg/L) in an aqueous solution and compared to single phase TiO 2 . The results show that the prepared photocatalyst was activated by visible light and used as effective catalyst in photooxidation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Ce-TiO 2 is tightly bound to Fe 3 O 4 and can be easily recovered from the medium by a simple magnetic process. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.