A broadband absorber using a double-layer frequency selective surface (FSS) loaded with resistors is proposed in this paper. Absorptivity is used to obviously characterize the performance of the absorber. Simulation results show that this kind of absorber can achieve Absorptivity of over 90% in the frequency range between 6.98 and 21.12 GHz (fractional bandwidth of 100.64%). Moreover, the structure has a thickness of 4 mm. The influence of the parameters of the proposed absorber on the absorption is then presented and analyzed.