Au-Ag bimetallic nanoparticle-supported microporous titanium silicalite-1 catalysts were prepared via a hydrothermal-immersion method, and their structures were examined. These materials serve as efficient catalysts for the photosynthesis of propylene oxide via the epoxidation of propene. The Au/Ag mass ratio and reaction temperature were demonstrated to have significant effects on the catalytic activity and selectivity of propylene oxide. The optimal formation rate (68.3 mu mol/g.h) and selectivity (52.3%) toward propylene oxide were achieved with an Au:Ag mass ratio of 4:1. Notably, the strong synergistic effect between Au and Ag resulted in superior photocatalysis of the bimetallic systems compared with those of the individual systems. A probable reaction mechanism was proposed based on the theoretical and experimental results. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.