In this paper, based on the frequency selection surface (FSS) of the traditional resonant split ring, on the basis of the finite element method and the semi-resonant ring periodic aperture structure, the Floquent period condition is used to simulate the infinite space element, and the scattering parameter and bandpass characteristics of the structure are obtained through the frequency domain solver. The shape of the structural unit is expanded to a crescent-shaped double-layer structure with reverse openings on the upper and lower surfaces, and the FSS of a multilayer semi-resonant ring coupling structure with a flat top transmission passband is optimized. The simulation results show that when the transverse magnetic wave is incident vertically, the resonant frequency of the semi-resonant ring structure is stable at 9 THz, the return loss at the center frequency is -22 dB, and it has good angular stability. The double-layer crescent-shaped structure can achieve multiple narrowband passbands at the resonance points of 5.9 THz, 10 THz and 11.7 THz, respectively. The multi-layer FSS structure has a transmission coefficient of less than -3 dB in the frequency range from 6.35 THz to 9.35 THz, and has good polarization stability. It provides a theoretical basis and technical support for the applications of FSS in the fields of terahertz non-destructive testing, communication and sensing.