The reduced graphene oxide wrapped Fe3O4 hollow nanospheres have been successfully synthesized by a simple self-assembly process driven by electrostatic interaction. The structure, chemical component and morphology were characterized by XRD, SEM, TEM, FTIR, and Raman spectroscopy. The fabricated nanocomposites exhibited superparamagnetic property with the saturation magnetization of 70.2 Am2 kg-1 at room temperature and allowed rapid separation under an external magnetic field. The high magnetism and excellent water dispersibility make these nanocomposites ideal candidates for various important applications such as magnetic resonance imaging, biosensors, communication, and microwave absorption.