Abstract: In this paper, a new procedure for designing frequency selective surface（FSS） composed of non-resonant elements is presented from the perspective of a equivalent circuit model. The procedure uses the periodic metallic patches and grids structure with the units of only λ/10 in dimensions, which realizes the similar property of the lumped bandpass filter network. Taking the advantages of the ripe theory of the lumped filter network and the convenience of high frequency circuit simulation software ADS and full-wave simulation software HFSS， the lumped bandpass filter network can be well designed and than converted to FSS element through an equivalent model. Compared with the traditional procedure， the new one simplifies the complicated calculation and makes the design more efficient. A sample of FSS fabricated to verify the validity of the design has been tested in the transmission coefficient system. The result meets the expectation and requirement of a stealthy radome, significantly reducing the radar cross section（RCS）.