In this study, a facile one-step Cyclic Voltammetry (CV) electrophoresis was proposed for designing a reduced graphene oxide/gold oxide (rGO/AuO_x) modified electrode by using chloride ions (Cl⁻) with the simultaneous occurrence of gold oxidation and GO reduction to induce the intimate attachment of negatively charged rGO sheets on the positively charged Au⁺/Au³⁺ clusters by electrostatic interaction. The surface microstructure and the oxygen functional groups of rGO/AuO_x can be tuned by controlling the dissolution rate of gold via the deposition scan rate. At a low deposition scan rate, the rGO/AuO_x electrode with well-dispersive rGO sheets and large active sites can induce rapid electron transfer to promote H₂O₂ detection. The amperometric response results displayed a relative fast response of less than 5 s with a low detection limit of 0.63 μM (S/N = 3). Also, the rGO/AuO_x neural-chemical interface can be modified at the multi-channels on neural probe and they exhibited excellent sensing performance to H₂O₂. The results demonstrated that the rGO/AuO_x modified electrode integrated with a neural probe using this one-step electrochemical deposition can provide a faster response and higher sensitivity by optimizing and controlling the surface microstructures of rGO/AuO_x, which would serve as a platform for medical application such as biosensors for multi-sensing.