Design a graphene sensor combining an open resonant ring metasurface with terahertz waves,more sensitive trace detection of different substances is achieved.When the symmetry of the resonant ring is broken,an interference phenomenon occurs between the electric dipole and the magnetic dipole,thereby forming a transparent window,and the resonance mecha-nism at the resonance point is further illustrated based on the multipole scattering power.The combination of metasurface and graphene enables the detection of imidacloprid insecticide at low concentrations with a detection limit of 1.725 fg/mL.This ul-tra-sensitive detection is achieved by the Fermi level of graphene moving to the Dirac point when there is a small change in the dielectric environment.The method is of great importance in enabling the detection of low concentrations of pesticides.