Hierarchical hybrid nanostructures are desirable materials for microwave absorption (MA) capacity. However, how to obtain this kind of versatile structural materials still remains a great challenge. In this work, a novel MA composite of MnO₂@NiMoO₄ was synthesized via two-step hydrothermal processes combined with a simple annealing process. As confirmed by X-ray diffraction, scanning electron microscopy, energy-dispersive spectrometry, and transmission electron microscopy analysis, the well-defined NiMoO₄ nanosheets could uniformly cover the surface of the MnO₂ nanorods. Compared with pure MnO₂ nanorods, these hierarchical composite structures could provide a higher superficial area, and more effective components, which will favor the penetration of microwaves into the absorber effectively instead of reflecting it, and then translate it into thermal energy. The minimum reflection loss (RL) value of MnO₂@NiMoO₄ composites was −31.4 dB at 11.2 GHz with a thickness of 3 mm, and the band of reflection loss was below −10 dB when frequency was in the range from 9.6 to 14.1 GHz. However, the minimum RL value of MnO₂ was only −12.5 dB at 10.4 GHz with a thickness of 3 mm. The significantly enhanced microwave absorption of MnO₂@NiMoO₄ composites is mainly attributed to the hierarchical hybrid nanostructures, multi-effective components, good impedance matching, and interfacial polarization between MnO₂ and NiMoO₄. Meanwhile, the surface attached NiMoO₄ is useful to increase the multiple reflection of electromagneticwaves. It is believed that these MnO₂@NiMoO₄ composites could serve as an excellent microwave absorber in practical applications.