Novel SrTiO3/BiOI heterostructure photocatalysts were successfully fabricated through a facile chemical bath method with assistant of the ethylene glycol. The photocatalysts were applied to minimize methyl orange (MO), bisphenol A (BPA), antibiotic oxytetracycline hydrochloride (OTTCH) under visible light irradiation. The SrTiO3/BiOI composites exhibited excellent photocatalytic performance towards the different refractory pollutants. Especially, the sample of STB-22.12 possessed the best photocatalytic performance in all the obtained catalysts. Several reaction parameters affecting degradation such as initial concentration, ion species were investigated systematically. Three-dimensional excitation-emission matrix fluorescence spectroscopy (3D EEMs) was used to further investigate the MO and OTTCH molecule degradation process. The photocatalytic mechanism over composite photocatalyst is systematically investigated by active species trapping experiments, ESR technique and Mott-Schottky measurements. Moreover, the energy band alignments of SrTiO3/BiOI heterostructure were confirmed via combining DRS and XPS analysis, which provided strong support for the proposed mechanism. This work could provide a deeper insight for the heterojunction catalyst. (C) 2017 Elsevier Inc. All rights reserved.