A novel carbon/sulfur composite has been fabricated by means of thermal and hydro-thermal treatments to serve as the cathode in Li–S batteries. The carbon matrix consists of graphene nanosheet (GS) and multiwalled carbon nanotube (MWCNT). The “GS/MWCNT@S” composite allows for infiltration of electrolyte into the cathode, assists in entrapment of polysulfide intermediates, and accommodates some of the stress and volume expansion that occurs during charge–discharge processes. In addition, the uniform distribution of sulfur in the conductive carbon matrix promotes utilization of the active materials. A Li–S cell containing the GS/MWCNT@S cathode delivered a capacity of 1290.8mAh/g and exhibited stable specific capacities up to 612.1mAh/g after 200 cycles at 0.1C. These results demonstrate that this cathode material is a promising candidate for rechargeable lithium batteries with high energy density.