Nitrogen-doped graphene quantum dots supported PtPd bimetallic nanoparticles was synthesized. The synergetic effect present in PtPd/N-GQDs@Au can increase the electrocatalytic activity towards hydrogen peroxide reduction. The novel PtPd/N-GQDs@Au based immunosensor possesses excellent sensitivity, special selectivity and long-term stability. The strategy provides a great promise in clinical application.