Photocatalytic degradation of pollutants in water has received much attention due to increasing environmental problems. In this study, a visible-light-driven plasmonic silver–graphene–bismuth tungsten (Ag–G–Bi₂WO₆) composite photocatalyst was prepared. Firstly, the graphite oxide (GO)–Bi₂WO₆ composite was prepared using a hydrothermal process, followed by a chemical reduction process using ethyl glycol (EG) as the reducing agent to form the G–Bi₂WO₆ composite. Then, Ag nanoparticles (NPs) were loaded onto the G–Bi₂WO₆ composite using a simple photochemical reduction process under xenon lamp irradiation to form the Ag–G–Bi₂WO₆ composite. The prepared samples were characterized using X-ray diffraction, transmission electron microscopy, nitrogen adsorption–desorption isotherm, UV-visible diffuse reflectance spectroscopy and electrochemical impedance spectroscopy. The photocatalytic activities of the prepared samples were evaluated by the photocatalytic degradation of rhodamine B (RhB) aqueous solution at ambient temperature under visible-light irradiation. The results showed that the photocatalytic activity of Bi₂WO₆ was significantly enhanced by the loading of Ag and graphene. The high photocatalytic activity is attributed predominantly to the hybridization of the surface plasmonic resonance (SPR) effect of Ag NPs and the specific electronics effect of graphene on the Bi₂WO₆ surface, thus enhancing the generation and separation of photogenerated charge carriers of Bi₂WO₆. Meanwhile, the excellent adsorption capacity of graphene also contributes to the enhancement of photocatalytic activity. This work highlights the design and preparation of new photocatalysts using plasmonic Ag and graphene as cocatalyst.