Here, we developed a simple and efficient route for the preparation of three-dimensional (3D) Co3O4-anchored graphene composites using the sacrificial template-assisted method and the subsequent deposition process of Co3O4 nanoparticles. As structural guiding materials, polystyrene (PS) spheres provide 3D porous architectures with a high surface area. 3D porous graphene materials serve as conductive supporters for the deposition of Co3O4 nanoparticles through precipitation growth. The 3D porous composite structures of Co3O4/graphene composites were intensively investigated using scanning electron microscope, transmission electron microscope, and X-ray diffraction. The 3D Co3O4/graphene composites show a high specific capacitance of 328Fg(-1) with efficient and fast charge-discharge process in aqueous 6M KOH electrolyte. In addition, the composites provide a good cycle lifetime, which retained 98% capacitance retention over 2000 cycles.