In order to construct a new non enzymatic electrochemical biosensor and use it for the effective detection of the release of H2O2 from cells,the graphene oxide(GO) modified by polydiallyl dimethyl ammonium chloride(PAC) and nano Pt were immobilized on glass carbon electrode(GCE) through the physical adsorption and electrodeposition of H2PtCl6 solution,respectively,and a Pt/PAC-GO/GCE electrochemical biosensor was successfully prepared.Through the characterization of scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS),it was observed that the electrodeposited nano Pt were densely covered and well distributed on the PAC-GO surface.Under the optimal experimental conditions,the Pt/PAC-GO/GCE biosensor exhibited a high peak current toward H2O2 and wide linear ranges for H2O2 in the range of 0.04-3.6 μmol/L and 4.4-28.6 μmol/L,with a detection limit of 0.01 μmol/L.Moreover,the Pt/PAC-GO/GCE biosensor exhibited excellent anti-interference capability and reproducibility for the detection of H2O2,and was also successfully used in the detection of H2O2 in different living cell.All these results proved that the prepared biosensor has a potential application in clinical diagnostics.