Novel visible light response Z-scheme Ag/AgI/WO 3 ÁH 2 O composite photocatalysts were synthesized using a two-step hydrothermal method followed by a photoreduction process without adding any surfactant. The synthesized Ag/AgI/WO 3 ÁH 2 O composite (AAW-2) with the Ag/WO 3 ÁH 2 O molar ratio of 0.8/1 showed the highest photodegradation activity for tetracycline hydrochloride (TCH) solution under visible light, and its rate constant was 24.6 times higher than that of WO 3 ÁH 2 O. The enhanced photocatalytic activity of the Ag/AgI/WO 3 ÁH 2 O composite can be due to the efficient separation of the electron-hole pairs through the Z-scheme Ag/AgI/WO 3 ÁH 2 O structure. The AAW-2 composite exhibited excellent stability toward TCH degradation after four successive circulations. Finally, the photocatalytic mechanism of the Ag/AgI/WO 3 ÁH 2 O composite was proposed based on the radical-trapping experiments, where h + and •O 2 À were the main active species during the photocatalytic reaction.