A magnetic BiOCl/Fe3O4 catalyst with simulated solar light response was successfully prepared through a precipitation process and characterized by X-ray diffraction, scanning electron microscopy, UV-vis diffuse reflectance spectroscopy, VSM, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy. The photocatalytic activity of BiOCl/Fe3O4 nanocomposites was further investigated through the photodegradation efficiency of carbamazepine (CBZ). In this study, 90.3% of CBZ was removed after 60 min irradiation in the presence of the BiOCl/Fe3O4 catalyst. Three reactive species were identified; the contribution of h(+), HO center dot, and O-2(center dot-) to CBZ degradation was approximately 94.98%, 3.25%, and 1.06%, respectively. The pH value had a significant effect on the CBZ degradation, and the best performance was achieved at pH 2.68. The presence of common anions (NO3-, Cl-, CO32-, and SO42-) also affected the CBZ degradation. The inhibiting effect followed the order of CO32- > SO42- > Cl-. However, NO3- weakly favored the photodegradation of CBZ. Moreover, the BiOCl/Fe3O4 photocatalyst could be easily recollected from the solution by applying an external magnetic field. This type of magnetic photocatalyst, which is characterized by ease of separation, may have application potential in wastewater treatment. The disappearance of CBZ as well as the formation of its products were determined by liquid chromatography mass spectroscopy and the possible photocatalytic degradation pathways were proposed. (C) 2017 Published by Elsevier Inc.