Frequency selective surfaces were analyzed by using a finite element method and the feasibility of simulating frequency selective surfaces by an Ansoft HFSS software was studied. By taking the frequency selective surfaces of a hexagon cell for example, the simulation method and process of the frequency selective surfaces were explored. A hexagon cell sample with frequency selective surfaces was fabricated by using a photolithography technology. The simulation curves were compared with the measured curves of the sample. The result showed that simulating the frequency selective surfaces by using the Ansoft HFSS was feasible. At the same time, the reliability of the simulation was further verified in the cirle and cross cell structure examples. In this simulation, both time domain characteristics and frequency domain characteristics of the frequency selective surfaces were considered. In contrast, either time domain characteristics or frequency domain characteristics could be considered in the traditional method. So, this simultaion method was more accurate.