Constructing two-dimensional (2D) carbon nanosheets into a three-dimensional (3D) framework can prevent restacking and increase the accessible surface area, which is promising to broaden the range of applications of 2D carbon materials. Here we report a facile preparation of an ultrathin, highly graphitized carbon nanosheets framework (UGCF) by directly carbonizing a gel composite of resol, FeCl3·6H2O, and F127 block polymer prepared by ball milling. During the carbonization process, the presence of FeCl3·6H2O in the resol-F127-Fe composite benefits the formation of highly graphitized structure, while F127 helps to introduce the porous architecture, resulting in an interconnected framework of carbon nanosheets. The unique carbon nanostructure of this UGCF has major advantages for electrochemical applications, owing to the large accessible geometrical surface, the rapid diffusion paths for ions, and the continuous transfer path for electrons through the graphitic framework. When used as anode in lithium-ion batteries, the UGCF shows excellent electrochemical performance in terms of capacity, rate performance, and cycle stability. This work provides a convenient and simple scale-up method to prepare highly graphitized carbon nanosheets with 3D nanoarchitecture.