Abstract: WO₃/graphene nanocomposites were successfully prepared with the simple low-temperature chemical synthesis method and they showed excellent photo-activated toluene gas-sensing properties at room temperature. The results showed that the addition of graphene would reduce the size of WO₃ lamella to about 300 nm and assemble it into a spherical structure. Graphene and WO₃ would form a chemical bond in the composite, effectively reducing the concentration of oxygen vacancies in WO₃. The photo-activated gas-sensing response of WO₃/graphene composite to 100 mL/m³ toluene under blue light was 3.3 times higher than that of pure WO₃. The material may have a good prospect for application in the explosive, flammable and toxic environment.