n this study, we prepared a novel electrocatalyst based on S doped reduced graphene layer modified with Ni and ZnO nanoparticles. The catalyst materials were characterized by X-ray Powder Diffraction (XRD), Raman spectroscopy, UV–vis spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and mapping. Because of the synergistic effect between three materials (S, Ni, and ZnO), the new electrocatalyst finally formed with a large electroactive surface area. Through the measurement, it was concluded that this surface includes large active sites which can effectively improve the electron transfer rate. The electrocatalytic activity of Ni-ZnO@s-rGO toward H2O2 reduction was examined via some measurements such as CV, I-t measurement, and electrochemical impedance spectroscopy. From CV measurement, the Ni-ZnO@s-rGO showed excellent electrocatalytic activity towards H2O2 accompanied by high current density with a reduction peak in the cathodic region. Our sensor exhibits a low detection limit of 0.16 µM, and with a good sensitivity value of 160.3 µAmM−1 under a wide linear range of analyte concentration from 1 µM-2000 µM. Besides, the proposed sensor electrode shows high selectivity toward H2O2.