In this paper, we have designed a proposed bimetal (copper (Cu)-nickel (Ni)) surface plasmon resonance (SPR) sensor based on graphene oxide (GO). Graphene oxide serves to enhance the surface electric field intensity, resulting in a substantial increase in sensitivity owing to its expansive surface area, superb electrical conductivity, chemical responsiveness, biocompatibility, and exceptional optical characteristics. The results of the simulation show that the integration of GO enhances the surface electric field intensity of the Cu-Ni layer, thereby potentially boosting the sensitivity of the proposed sensor. According to the simulation results, bimetal thicknesses of 39 nm and 5 nm achieve a remarkable figure of merit (FoM) of 68.59/RIU, with a maximum sensitivity of 385.37°/RIU. The exceptionally high sensitivity and stability exhibited by this proposed sensor make it highly promising for biosensing and medical diagnosis applications.