The CeVO₄/graphitic C₃N₄ composites have exhibited much enhanced photocatalytic property for degrading methylene blue (MB) pollutant under visible light irradiation compared with single-phase g-C₃N₄ or CeVO₄. The composite S5 obtained from an optimized mass ratio (5%) of CeVO₄ to dicyanamide (DCDA) exhibits the highest photocatalytic activity. Here, ternary Ag/CeVO₄/g-C₃N₄ composites denoted as X%Ag/S5 were prepared by an ultrasonic precipitation method to improve the photocatalytic property of S5. The TEM images show that CeVO₄ and Ag nanoparticles are well distributed on the layered g-C₃N₄, which agree well with the XRD results. The UV spectra show that the 7%Ag/S5 sample has the widest absorption range and the enhanced absorption intensity under visible light irradiation. The corresponding band gap of 7%Ag/S5 (2.5 eV) is much lower than that of S5 (2.65 eV). The corresponding k value of 7%Ag/S5 is much higher than those of g-C₃N₄ and CeVO₄. The degradation experiments for MB solution suggest that the 7%Ag/S5 sample has the optimal photocatalytic performance, which can degrade MB solution completely within 120 min. The enhanced photocatalytic property of the composites is ascribed to not only the effect of heterojunction structure, but also the surface plasma resonance effect of Ag nanoparticles.