We report electric field tuning of surface plasmon resonance (SPR) by controlling the polarization state of incident light using vertical alignment liquid crystal (VA-LC) layer. Excitation of SPR depends on the polarization state of incident light and incident angle. We fabricated a metallic grating structure in order to excite SPR, and then we investigated the applied voltage dependence of reflection spectrum. Continuous tuning of SPR is achieved as a result of the polarization change of incident light by controlling the birefringence of the LC layer.