To increase the energy density of supercapacitors to approach that of batteries, the current research is always directed towards the cathode materials, whereas the anode materials are rarely studied. In the present work, single-crystalline Fe2O3 nanoparticles directly grown on graphene hydrogels are investigated as high performance anode materials for supercapacitors. During the formation of the graphene/Fe2O3 composite hydrogels, flexible graphene sheets decorated with Fe2O3 particles are self-assembled to form interconnected porous microstructures with high specific surface area, which strongly facilitate charge and ion transport in the full electrode. Infrared spectra show that hydrogen bond is formed between C–OH on graphene hydrogels and Fe2O3. Benefits from the combined graphene hydrogels and Fe2O3 particles in such a unique structure are that the graphene/Fe2O3 composite electrode exhibits an ultrahigh specific capacitance of 908Fg−1 at 2Ag−1 within the potential range from −1.05 to −0.3V, and an outstanding rate capability (69% capacity retention at 50Ag−1). Furthermore, the cycling performance is clearly much better for the graphene/Fe2O3 composite hydrogels than that for pure Fe2O3 sample. These findings open a new pathway to the design and fabrication of three-dimensional graphene hydrogel composites as anode materials in the development of high-performance energy-storage systems. Three-dimensional graphene/Fe2O3 composite hydrogels show ultrahigh specific capacitance and outstanding rate capability. Display omitted •Flexible graphene sheets decorated with Fe2O3 particles are self-assembled to form interconnected porous microstructures.•IR spectra show intramolecular hydrogen bonding is formed in grapheme/Fe2O3 composite hydrogels.•Graphene/Fe2O3 composite electrode exhibits ultrahigh specific capacitance of 908Fg−1 at 2Ag−1 within the potential range from −1.05 to −0.3V, and outstanding rate capability (69% capacity retention at 50Ag−1).•Cycling performance is clearly much better for the graphene/Fe2O3 composite hydrogels than for pure Fe2O3 sample.