Poly 3,4–Ethylene Dioxythi Ophene:Poly 4–Styrene Sulfonate(PEDOT:PSS) is a promising candidate for Terahertz(THz) multifunctional materials. In order to verify the possibility of PEDOT:PSS replacing metals in terahertz Metamaterials(MMs), a terahertz Frequency Selective Surface(FSS) based on Dimethyl Sulphoxide(DMSO)-doped PEDOT:PSS films is designed and simulated by Computer Simulation Technology(CST) Microwave Studio software. Strong band rejection with a modulation depth of 50 dB can be achieved at resonant frequencies.