In order to improve the weak dielectric loss capability and poor impedance matching of Fe3O4, the hexagonal plates of Fe3O4/Fe2O3/C nanocomposites were rationally constructed in this paper by utilizing electrostatic attraction and cross-linking, using polyacrylamide (PAM) as templating agent and viscosity modifier. The stacked hexagonal plates constructed a conductive network and utilized the structural properties of Fe3O4 to promote the transfer and jump of free electrons, which effectively improved the conduction loss. The heterogeneous interface was effectively constructed due to the presence of Fe2O3 and trace carbon, while the transfer and leap of free electrons promoted the generation of interfacial polarization, resulting in magnetoelectric coupling and effective improvement of polarization loss. The results show that the effective absorption broadband reaches 4.08GHz when the matching thickness of the composite is 2mm. A minimum reflection loss of -43.79dB is realized at a matching thickness of 1mm. The PAM modification proved to be an effective means to modulate the morphology and composition of the materials.