In this study, the optimization of the surface plasmon resonance (SPR) sensor based on graphene–silver substrate was investigated. We simulated the reflection spectrum that depends on the metal thickness and the number of graphene layers. The addition of a certain number of graphene layers based on the knowledge that silver oxidation decreases the sensitivity of the sensor improved the sensitivity SRI, while the detection accuracy decreased. To optimize the sensor performance, the investigation focused on monolayer graphene. Furthermore, genetic algorithms were used to optimize the SPR biosensor reflection by adjusting the coefficients of the system, which are the incidence angle and metal layer thickness.