Graphene and Fe3O4 were bound by electrostatic attraction and prepared by effective reduction through microwave treatments. As a result of fabricating graphene with Fe3O4 as a composite material, it has been confirmed that it contributes to the structural improvement in graphene stabilization and at the same time, it shows improved electrochemical performance through improved charge transfer. It was also confirmed that the crystalline Fe3O4 was uniformly dispersed in the rGO sheet, effectively blocking the reaggregation due to the van der Waals interaction between the neighboring rGO sheets. The structural analysis of prepared composites was confirmed by transmission electron microscopy, and X-ray diffractometer. Electrochemical properties of composites were studied by cyclic voltammetry, galvanostatic charge–discharge curves, and electrochemical impedance spectroscopy. The Fe3O4 (0.4 M)/rGO composite showed a high specific capacitance of 972 F g−1 at the current density of 1 A g−1 in 6 M KOH electrolyte, which is higher than that of the pristine materials rGO (251 F g−1) and Fe3O4 (183 F g−1). Also, the prepared composites showed a very stable cyclic behavior at high current density, as well as an improvement in comparison with pristine materials in terms of resistance.