The hierarchical structures of carbonized melamine foam modified by FeNi alloy and silicon layer (CMF/FeNi-SiO 2) have been fabricated by a magnetron sputtering method. The as-prepared CMF/FeNi-SiO 2 composites exhibited a three-dimensional porous structure, with the framework uniformly covered by a 150~400 nm FeNi layer and an ultrathin SiO 2 layer, which demonstrated soft magnetic properties at room temperature. Moreover, the microwave absorption performance of the foam was investigated in the frequency range from 2 to 18 GHz. The results showed that the microwave absorption performance of CMF/FeNi-SiO 2 composite was significantly enhanced in the low-frequency range compared with CMF/FeNi. The minimum reflection loss of CMF/FeNi-SiO 2 with an absorption thickness of 4.1 mm was about −53 dB at 3.38 GHz and reached an effective absorption bandwidth of 0.93 GHz (from 2.93 GHz to 3.86 GHz). The frequency bandwidth of 4 GHz (2.35~6.35 GHz) with absorption loss ≤ −10 dB and the frequency bandwidth of 2.05 GHz (2.62~4.67 GHz) with absorption loss ≤-20 dB demonstrated the CMF/FeNi-SiO 2 a high-efficient absorber in the low-frequency band (2-6 GHz), which stemmed from improved impedance matching and attenuation capacities.