In this paper, Ag/Ag3PO4/Bi2SiO5 nanocomposite was synthesized by ultrasonic-assisted precipitation method. The morphology and structure and optical properties of Ag/Ag3PO4/Bi2SiO5 were characterized by XRD, SEM, EDS, HRTEM, XPS, BET, and UV–Vis DRS. The photocatalytic activity of Ag/Ag3PO4/Bi2SiO5 was evaluated by degrading Rhodamine B (RhB) solution under visible-light irradiation. Compared with Ag3PO4/Bi2SiO5, the photocatalytic activity of Ag/Ag3PO4/Bi2SiO5 was improved, which may be due to the plasmon resonance effect of Ag. Ag doping improves the charge transfer and light absorption capacity of Ag/Ag3PO4/Bi2SiO5 heterojunction. After 90 min of visible-light irradiation, the degradation efficiencies of MB, RhB, and MO by Ag/Ag3PO4/Bi2SiO5 were 100%, 99.89%, and 85.88%, respectively. It was shown by free radical trapping experiments that h+ was the main active species in the degradation of RhB by Ag/Ag3PO4/Bi2SiO5, while ·O2− and ·OH played a secondary role.