Ciprofloxacin (CIP) has been a serious threat to the ecological environment and human health due to extensive application and persistence. Low concentrations of CIP can cause toxic effects on the surface and ground waters. It is critical to fabricate accurate and sensitive detection platform of CIP. Herein, a photoelectrochemical detecting platform of CIP has been constructed using metallic Bi self-doping BiOBr (Bi/BiOBr) composites. The Bi/BiOBr composites can be synthesized by a facile ethylene glycol (EG)-assisted solvothermal method. The metallic Bi nanoparticles can evenly distribute on the surface of BiOBr microspheres. In order to the incorporation of metallic Bi nanoparticles, the Bi/BiOBr composites exhibit excellent photoabsorption property and photoelectric conversion efficiency in visible region. Consequently, the result of photoelectrochemical measurements shows that the photocurrent density of Bi/BiOBr composites is superior to pure BiOBr. The increased photoelectrochemical properties of Bi/BiOBr composites are attributed to the efficient separation of electron-hole pairs and rapid electrons transfer. In addition, the photoelectrochemical sensor based on Bi/BiOBr composites has been constructed for sensitively detecting CIP. The photoelectrochemical sensor exhibits a good linear relationship, a low detect limitation and relatively stability for monitoring CIP. (c) 2017 Elsevier Ltd. All rights reserved.