Boosting gravimetric and volumetric capacitances simultaneously at a high rate is still a discrepancy in development of graphene based supercapacitors. We report the preparation of dense hierarchical graphene/activated carbon composite aerogels via a reduction induced self-assembly process coupled with a drying post treatment. The compact and porous structures of composite aerogels could be maintained. The drying post treatment has significant effects on increasing the packing density of aerogels. The introduced activated carbons play the key roles of spacers and bridges, mitigating the restacking of adjacent graphene nanosheets and connecting lateral and vertical graphene nanosheets, respectively. The optimized aerogel with a packing density of 0.67 g cm(-3) could deliver maximum gravimetric and volumetric capacitances of 128.2 F g(-1) and 85.9 F cm(-3), respectively, at a current density of 1 A g(-1) in aqueous electrolyte, showing no apparent degradation to the specific capacitance at a current density of 10 A g(-1) after 20000 cycles. The corresponding gravimetric and volumetric capacitances of 116.6 F g(-1) and 78.1 cm(-3) with an acceptable cyclic stability are also achieved in ionic liquid electrolyte. The results show a feasible strategy of designing dense hierarchical graphene based aerogels for supercapacitors. (C) 2016 Elsevier B.V. All rights reserved.