Abstract: An electrically controlled terahertz wave switch was designed and proposed based on double layer graphene structure. The switch was made up of prism-graphene-SiO2-graphene-InSb. The terahertz wave was incident from the left side of the prism at a specific angle, and the terahertz wave detector was fixed on the right side of the prism. By adjusting the external voltage bias, the refractive index of the graphene layers was changed in order to control the reflectance to achieve the purpose of terahertz switching. COMSOL software was used to simulate the double-layer graphene electronic switch.Terahertz wave with frequency of 1 THz was incident at 35.42 from the top of the prism in experiment. When there was no external electric field, the reflectivity of terahertz wave was 2.63%, which was defined as the off state of the terahertz wave switch. When the applied electric field was applied, the dielectric constant of graphene changed, and the reflectivity of terahertz wave changed to 93.01%. The structure of prism was close to total reflection, which was defined as the open state of terahertz wave switch. The simulation results show that the device has good performance in controlling the intensity of the terahertz wave. Extinction ratio of the switch was 15.5 dB.