Based on the theory of plasmon resonance， we present a photon plasma ridge waveguide consisting of a metal/graphene/Al₂O₃/graphene stacking structure. The modulation performance is optimized through the design of the waveguide and plasma structures by analyzing the microscopic mechanism of photoelectric reaction. A low-insertion-loss near-infrared electro-optic modulator with a modulation rate of 730 GHz， energy consumption of 0.7 fJ/bit， and 3-dB bandwidth of 3.66 THz is achieved.