Herein, we report a novel approach to polyvinyl pyrrolidone k-30 (PVP)-templated formation of fluorescent gold nanoparticles (Au NPs) with pore structure and its application to sewage detection. For the first time demonstrate the method of generating PVP-encapsulated Au NPs in aqueous solution. It was found that the formation of fluorescent Au NPs have highly fluorescence signal. Through the adsorption experiment, it is concluded that the methylene blue is adsorbed on Au NPs. This work successfully develops the capping PVP scaffolds of fluorescent Au NPs with pore structure. This experiment lays a foundation for the application of Au NPs in the field of environmental.