CdWO4/g-C3N4 composite photocatalysts have been successfully synthesized by a simple mixed-calcination method for the first time. X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and diffuse reflection spectroscopy (DRS) were carried out to analyze the crystal structure, morphology and optical property of the as-prepared samples. The photocatalytic experiments on rhodamine B (RhB) degradation showed that the 1:10 CdWO4/g-C3N4 photocatalyst exhibited the highest efficiency for degradation of RhB under visible light (lambda > 420 nm), which was almost 1.6 and 54.6 times as high as those of the pure g-C3N4 and CdWO4, respectively. This enhancement in visible-light photocatalytic activity of CdWO4/g-C3N4 composite should be attributed to the matchable band structures and interfacial interaction between CdWO4 and g-C3N4, resulting in the efficient separation and transfer of photogenerated charge carriers. It was corroborated by the photoluminescence spectroscopy (PL) and active species trapping experiments. (C) 2015 Elsevier B.V. All rights reserved.