A p-n heterojunction film of Cu2O/alpha-Fe2O3 was constructed by electrodepositing p-type Cu2O microcubes on liquid phase deposited film of n-type alpha-Fe2O3. The surface morphology, the crystal phase and composition of Cu2O/alpha-Fe2O3 heterojunction film were characterized by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The enhanced absorption in the visible light region was observed in UV-visible diffuse reflectance spectra. Meanwhile, an efficiently improved separation and faster transfer of photogenerated electrons and holes were revealed by photoluminescence spectra and electrochemical impedance spectra. The Cu2O/alpha-Fe2O3 p-n heterojunction was applied to photoelectrocatalytic degradation of oxytetracycline at a bias potential of +0.5 V under visible light illumination. After 60-min photoelectrocatalytic treatment, 73.3% of oxytetracycline was removed and the degradation rate constant reached 2.14 x 10(-2) min(-1). Moreover, the crystal phases and compositions for the used and fresh Cu2O/alpha-Fe2O3 films were studied, and a possible photoelectrocatalytic mechanism was proposed. (C) 2018 Elsevier Inc. All rights reserved.