In this work, we growth silver nanoplates on graphene oxide (GO) as an electrochemical sensor for detecting hydrogen peroxide (H2O2). Silver nanoplates on GO were obtained by the in-situ photoreduction method at 540 nm excitation wavelength. The nanocomposites were characterized using UV-Vis spectroscopy, Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Transmission electron microscopy (TEM), Raman spectroscopy, and the electrochemical properties were measured by cyclic voltammetry (CV). Our results reveal the transformation of quasi-spherical silver nanoparticles from 12 nm to planar faces of 25 nm on GO. The preeminent detection range for H2O2 determination was 0.4 mM to 3 mM with a detection limit of 0.28 mM and sensitivity of 444.51 µA mM−1 cm−2. The results reveal that a synergistic effect between silver nanoplates on GO enhances the electrochemical properties for the determination of H2O2.