In this work, nanowire-nanocone double-layer nanoforests are prepared based on a plasma repolymerization technique, and then double-layer hybrid nanoforests are realized by introducing noble metal-nanoparticles on surface of the nanoforests using a magnetron sputtering step. The entire process is simple and fully compatible with conventional micro-fabrication, besides, it is a parallel technique, thus large area fabrication of the hybrid nanoforests is easy to achieve. Moreover, such a hybrid nanoforest is able to combine light trapping effect and surface plasmonic effect thus to achieve an average absorption as high as 84.1% in a broad wavelength range of 1.5~25 μm. With such a broadband high absorption property, the double-layer hybrid nanoforests are expected to be widely used to improve performance of infrared devices, and to expand applications of such devices.