Visible-light-driven tetrahedral Ag/Ag3PO4 photocatalyst with exposed {111} facets was successfully fabricated by a facile microwave-assisted chemical reduction method. Ag nanoparticles were in-situ synthesized on the {111} planes of Ag3PO4 with the assistance of pyridine and polyvinylpyrrolidone (PVP). Ag decorated Ag3PO4 exhibits excellent visible-light absorption and low recombination rate of charge carriers. The photocatalytic performance of the Ag/Ag3PO4 composites were evaluated by degradation of Rhodamine B (RhB) under simulated sunlight irradiation (λ>410 nm). The investigations show that the active {111} planes of tetrahedral Ag3PO4 are conducive to enhancement of visible-light photocatalytic activity. Besides, Ag/Ag3PO4-0.05 composite exhibit the highest photocatalytic activity, the deposition of Ag nanoparticles on the {111} planes of Ag3PO4 can effectively improve the photocatalytiy activity and stability of Ag3PO4 due to the Schottky junction and localized surface plasmon resonance (LSPR) effect of Ag nanoparticles. The photocatalytic mechanism of the Ag/Ag3PO4 composite was also proposed.