Adjustable and high-performance microwave absorbing materials of three-dimensional (3D) reduced graphene oxide (RGO)@Fe3O4 structure were realized with different compositions. 100 x 50 nm Fe3O4 nanorods were anchored on both sides of RGO sheets uniformly which stop RGO sheets from re-stacking. Effective absorption bands shifted to higher frequencies and thinner thicknesses in 2-18 GHz due to the precisely controlled complex permittivity caused by the decreased content of RGO. The maximum reflection loss of RGO@Fe3O4 composites was up to - 56.25 dB at 12.62 GHz with a small thickness of 2.0 mm, and the absorption bandwidth below - 10 dB was 5.40 GHz with only 20 wt% filler loading in the paraffin matrix. The dielectric loss was a primary factor in the superior absorption performance resulting from dipolar polarization, interfacial polarization and associated relaxation phenomena. Hence, the appropriate composition of the RGO@Fe3O4 structure can consider both the microwave absorptivity and the absorption adjustability. This method can be apply to other graphenebased magnetic microwave absorption materials.