A novel electrochemical biosensor for sensitive detection of hydrogen peroxide (H2O2) was developed on the basis of polyethyleneimine-Au nanoparticles-zinc protoporphyrin (PEI-AuNPs-ZnPP). In this approach, PEI-AuNPs-ZnPP was prepared by coupling carboxyl of ZnPP with amino of PEI-AuNPs. Transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR) were used to characterize the formation of PEI-AuNPs-ZnPP. Under optimal conditions, this strategy showed a good sensitivity for H2O2 detection with a low detection limit of 0.0861 pM. What's more, this biosensor can be successfully applied for the measurement of H2O2 in human serum samples. These results suggested that PEI-AuNPs-ZnPP could be a good candidate for H2O2 detection in complicated biological samples. (c) The Author(s) 2019. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: [email protected].