A novel smart catalytic system was successfully constructed by using poly[(dimethylamino)ethyl methacrylate] (PDMAEMA) brush grafted graphene oxide (GO) to load gold nanoparticles (Au NPs). The catalytic activity of the Au NPs was finely tuned by temperature, which can control the inclusion and ‘exposure’ of Au NPs inside the PDMAEMA brushes via the phase transition of the grafted PDMAEMA chain triggered by a temperature above the lower critical solution temperature (LCST) of PDMAEMA.