In this study, surface plasmon-enhanced nanolasers beyond the optical diffraction limit with different structural parameters have been designed and analyzed to optimize the surface plasmon coupling efficiency. Electric field energy can be highly confined in the ultrathin insulating region, as revealed via simulated distribution of the electric field using COMSOL Multiphysics software, resulting in an enhanced stimulated emission of radiation. Additionally, through optimizing the structural parameters, the optical performance of plasmon-enhanced nanolasers was significantly improved, with a threshold as low as ∼4 W cm−2 and a Quality (Q) factor of up to 196 under optical pumping.