In this paper，prussian blue(PB) coated gold nanoparticles(Au NPs) were firstly prepared by in situ method.Then，polydopamine(PDA) wrapped Au-PB was synthesized based on the characteristic of one-step oxidative polymerization of dopamine.The bioinspired surface enriched amino and hydroxyl groups were further used as a support to anchor active platinum nanoparticles(Pt NPs).Horseradish peroxidase(HRP) functionalized Au-PB-PDA-Pt nanocomposites was also used for the fabrication of H2O2 biosensor.By taking advantages of the excellent biocompatibility and film forming ability of PDA，the large surface area and high biocompatibility of Pt NPs，and the synergistic employ of PB，Pt and HRP，the HRP functionalized nanocomposites modified electrode exhibited an excellent electroreduction activity to H2O2.Under the optimum conditions，the linear detection range from 2.0×10-7-1.0×10-3 mol?L-1 was observed,and a detection limit was 1.2×10-7 mol?L-1.