This paper focuses on the research of graphene chiral metasurfaces, which is mainly concentrated in the mid-infrared band, while there are relatively few studies on devices in the terahertz band, and the problem of insufficient circular dichroism generated by the non-intrinsic structure of graphene. Based on the properties of graphene, a double-layer graphene chiral metasur-face structure is designed. There is a certain angle between the upper and lower graphene patterns of the structure. By adjusting the size of this angle and the thickness of the intermediate silicon dioxide layer, the circular dichroism of the metasurface structure is studied. In addition, the dynamic tuning ability of the metasurface structure is analyzed by changing the Fermi level and relaxation time of graphene. The simulation results show that the metasurface structure can achieve circular dichroism in the terahertz frequency band and has the ability of dynamic tuning.