Three dimensional (3D) iron oxide (Fe2O3)/graphene aerogel (GA) hybrid (Fe2O3/GA) was synthesized by a novel in situ hydrothermal method. Due to the high surface area and sponge structure of GA, which facilitate the access of electrolyte to the internal surface of the graphene film, this 3D Fe2O3/GA composite consequently lead to a robust and superior hybrid material with higher capacitance and better rate performance compared to that of the stacked Fe2O3/graphene (Fe2O3/G) hybrid when used as electrode materials in supercapacitors (SCs). Furthermore, a highly flexible all-solid-state symmetric supercapacitor device was fabricated by two pieces of our Fe2O3/GA hybrid electrode. The device is suitable for different bending angles and delivers a high specific capacitance of 440 F g−1. 90% capacitance was retained over 2200 cycles, indicating good cycling stability. These excellent electrochemical performances suggest that Fe2O3/GA composites have an enormous potential in energy application.