Developing nanomaterials with efficient electromagnetic wave absorption to eliminate increasingly serious electromagnetic pollution is of great significance. The peculiar electromagnetic characteristics of one-dimensional dielectric-magnetic heterostructures bring a promising strategy for designing high-efficiency absorber. Herein, a hierarchical PPy@FeCo@PPy nanotube was fabricated through a process of oxidative polymerization and electroless plating. In the product, the FeCo nanoparticles are encapsulate in the middle of the polypyrrole (PPy) dual conductive layers, which facilitates the deep construction of heterointerfaces and simultaneously prevents magnetic agglomeration. Furthermore, the hollow structure and suitable dielectric-magnetic component optimize impedance matching. Profiting from the reasonable structural design and the strong synergistic loss mechanism of dielectric-magnetic, the coaxial multi-shell PPy@FeCo@PPy nanotube exhibits prominent electromagnetic wave absorption performance, with a minimum reflection loss of −50.5 dB and the effective absorption bandwidth of 5.7 GHz at 2.0 mm. This work offers a gentle strategy for preparing ideal microwave absorbers by constructing dielectric-magnetic heterogeneous interfaces.