It is a novel and practical method to use natural porous biomaterials as microwave absorber. In this study, NixCo1S nanowires (NWs)@diatomite (De) composites with one-dimensional (1D)-NWs and three-dimensional(3D)-De composites were prepared by a two-step hydrothermal method using De as template. The effective absorption bandwidth (EAB) of the composite reaches 6.16 GHz at 1.6 mm and 7.04 GHz at 4.1 mm, covering the entire Ku band, and the minimum reflection loss (RLmin) is less than −30 dB. The excellent absorption performance is mainly due to the bulk charge modulation provided by the 1D NWs and the extended microwave transmission path within the absorber, coupled with the high dielectric loss and magnetic loss of the metal-NWS after vulcanization. We present a high-value method that combines vulcanized 1D materials with abundant De to achieve the lightweight broadband efficient microwave absorption at the first time.