Abstract: The multi-layer structure with frequency selective transmission and absorption properties is designed in this paper, which is a new technique to absorb out-of-band electromagnetic waves while the antenna is working normally. It has many advantages, such as wide stealth band, strong structural strength and high electromagnetic compatibility of electronic equipment. This paper analyzes the equivalent circuit model of some typical frequency selective surface (FSS) elements, and deduces the equivalent circuit model of the multi-layer structure with frequency selective transmission and absorption(FSTA) properties, in this way we obtain an efficient and quick identification of new structure and the rules of parameters' effects on structural behavior. By simulation and optimization, we obtain the structure of transmission at low frequency and absorption at high frequency(LTHA).