Sr2/3Zn1/3TiO3 (1) and Ba5/6Zn5/6TiO3 (2) with perovskite structure have been prepared by a facile sol gel method, among which the A sites (Sr and Ba for 1 and 2, respectively) were partially replaced by zinc ions. The photocatalysts were characterized by powder X-ray diffraction, UV-vis diffuse reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The results of photocatalysis experiment showed that both 1 and 2 exhibited good activity for water reduction to form H-2 without cocatalysts loading under ultraviolet light irradiation. Compared with pure SrTiO3 and BaTiO3, 1 and 2 showed remarkable improvement in H-2 production efficiency, respectively. And the photocatalytic mechanisms of them were investigated by the theoretical method. This study demonstrated that the substitutional doping of appropriate ions could change the crystal and band structures and significantly promote electron transport in catalysts, which result in their good photocatalytic activities. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.