▎ 摘　　要

Although terahertz radiation can be generated when the electron beam is moving in parallel with the graphene layer loaded on periodic grating structure, there still have some difficulties about the tuning method. Here, we propose a method that by changing the direction of the liquid crystal (LC) molecules to dynamically tune the radiation frequency over a wide range at room temperature. The THz radiation generated by an electron beam moving atop graphene coated on a LC grating structure. This method will be helpful to the future applications of tunable terahertz source in miniaturization.