A novel Ag 3 PO 4 /reduced graphene oxide/Ag nanocrystals (Ag 3 PO 4 /RGO/Ag) heterostructure photocatalyst has been synthesized using a facile photo-assisted reduction method for the first time. The Ag 3 PO 4 /RGO/Ag that consists of close chemical bonding between RGO and Ag 3 PO 4 nanoparticles as well as dispersive plasmonic Ag nanocrystals on the RGO sheets exhibited superior photocatalytic activity and stability to bare Ag 3 PO 4 , Ag/Ag 3 PO 4 and Ag 3 PO 4 /GO in degradation of Rhodamine B and phenol under visible light. It is suggested that the photo-generated electrons in Ag 3 PO 4 can be transferred to RGO/Ag, leading to efficient separation and transfer of electron–hole pairs. Meanwhile, under light irradiation, the plasmonic Ag nanocrystals also generate electron–hole pairs through surface plasmon resonance (SPR), in which the active electrons can facilitate the formation of additional active species of O 2 • − for photocatalysis whereas the holes can be filled by electrons from RGO. As a result, both the photocorrosion of Ag 3 PO 4 and the recombination of electron–hole pairs are suppressed due to the special electron transfer route of Ag 3 PO 4 →RGO→Ag in the heterostructure. This work suggests that the reasonable combination of semiconductors and graphene decorated with noble metallic nanocrystals can provide a versatile strategy for the synthesis of high efficient heterostructed photocatalysts.