In general, the preparation and photocatalysis of a semiconductor photocatalyst are carried out in two discrete reaction systems. Here we reported the simultaneous achievement of fabrication and in-situ photocatalysis of Ag/Bi2WO6 heterostructures in one system. By irradiating AgNO3/Bi2WO6 suspended organic pollutant solutions under simulated sunlight, Ag/Bi2WO6. heterostructures were on-line obtained via the photoreduction of AgNO3 and instantly participated in photocatalysis. The facile one-system process is rather time- and energy consumption. The results showed that monodispersed Ag nanoparticles of 10-20 nm were firmly anchored on Bi2WO6 surface. The decoration of Ag effectively broadened the visible-light response of Bi2WO6 and inhibited the recombination of photogenerated electron-hole pairs. The synergistic effect between Ag and Bi2WO6. brought about obviously enhanced photocatalytic activity to degrade organic contaminants compared with bare Bi2WO6. The sample with Ag molar ration of 0.1 presented the optimum photodegraded efficiency with rate constant 3.1-folds of Bi2WO6. And the composite is easily recovered with excellent circulation stability. The work provides some insights into the rational design and development of in-situ photocatalysis with high performance, which is more preferred for practical application. (C) 2015 Elsevier B.V. All rights reserved.