Co9S8 has attracted much attention as a promising electrode material for energy storage owing to its superior electrochemical capacity. However, its poor stability and electronic conductivity, which results in inferior cycling performance and rate capability has seriously limited the practical application of Co9O8 in supercapacitors (SCs). Herein, Co9S8 nanoparticles were embedded in reduced graphene oxide (rGO) via a simple anneal approach as high efficient and stable electrodes for SCs. The Co9S8/rGO composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD). The Co9S8 nanoparticles were inserted tightly between the layers of rGO due to strong inter-molecular forces, preventing the cluster in reduction process of rGO from graphene oxide (GO). The rGO provides the conductive network for Co9S8 and shortens the ion diffusion paths, which led to improve rate performance and enhance the stability of the electrode material. The as-prepared Co9S8/rGO takes full advantages of high capacitance performance of Co9S8 nanoparticles and excellent conductivity and electrochemical stability of rGO. Thus Co9S8/rGO composites exhibit high specific capacity of 708.3 F g-1 at current density of 1A g-1. In addition, the asymmetric hybrid supercapacitor (Co9S8/rGO//rGO) delivered an excellent energy density of 41.1 Wh kg-1 and a high-power density of 750.3 W kg-1. The Co9S8/rGO composites introduced here represents a high efficient ideal electrode that can be easily applied in automotive filed with excellent performance.