▎ 摘　　要

NOVELTY - The composite material comprises annular iron oxide (Fe3O4) nanoparticles, reduced graphene oxide coated with the annular Fe3O4, and a polyaniline located in the pore of the annular Fe3O4. USE - The composite material is useful in electromagnetic wave absorption field (claimed). ADVANTAGE - The composite material has thin thickness, low density, wide frequency band, and strong absorption. The method is simple and fast, less influence factor, easy control, safety environment-friendly, and provides the composite material with improved wave-absorbing performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a preparation method of composite material comprising mixing and reacting the annular Fe3O4 nanoparticles, oxidized graphene and polyaniline in medium, separating solid and liquid of the obtained reaction product, taking solid product, and drying to obtain the composite material.