Visible-light-driven semiconducting photocatalysts of Ag3PO4 were prepared by a hydrothermal method, and were optimized by adjusting reaction conditions, i.e., temperature, pH of reaction solution, concentration of feedstock, and time of hydrothermal process. The obtained photocatalysts were then systematically characterized by different instruments, such as XRD, UV-vis, FESEM, and BET, to reveal the physicochemical properties. Furthermore, activities of photocatalysts for visible-light-driven O-2 evolution were evaluated, demonstrating that the photocatalytic activity of Ag3PO4 prepared by hydrothermal reaction (initial rate of O-2 evolution, 1156 mu mol g(-1) h(-1)) was more than two times as that of sample prepared by room-temperature reaction (initial rate of O-2 evolution, 533 mu mol g h(-1)), which could be attributed to its better ability to utilize visible light and more regulated morphology. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.