g-C3N4/Ag3PO4 heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The photocatalysts were characterized by X-ray powder diffraction, transmission electron microscopy, UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic activities of the obtained samples were tested by using Rhodamine B (RhB) as the degradation target under visible light irradiation. g-C3N4/Ag3PO4 decomposed RhB, more effectively than the pure Ag3PO4 particles did, and 2 wt.% g-C3N4 had the highest activity. Furthermore, 2 wt.% g-C3N4/Ag3PO4 degraded high-concentration RhB more potently than unmodified Ag3PO4 did, probably because g-C3N4/Ag3PO4 heterojunction photocatalyst enhanced the photocatalytic activity by efficiently separating the photogenerated electron-hole pairs. (C) 2014 Published by Elsevier Ltd.