Highly ordered, body-centered cubic mesoporous phenol–formaldehyde carbon C-FDU-16 is prepared by a facile evaporation induced self-assembly strategy under a basic aqueous condition. Afterwards, in order to increase the active site of surface electrochemical reactions and promote the wettability in aqueous electrolyte, a simple chemical surface modification is carried out on the C-FDU-16 by nitric acid treatment. The C-FDU-16 and the acid-modified C-FDU-16 (N-FDU-16) are used as the active materials for supercapacitors. Although C-FDU-16 has unique 3D mesoporous network combined with high specific surface area, it do not show well supercapacitor properties for its bad wettability with the aqueous electrolyte. However, the N-FDU-16 with acid treatment exhibits the largest specific capacitance of 219 F g−1 at a current density of 0.1 A g−1 in 1 M H2SO4 electrolyte which is 7 times larger than that of the C-FDU-16 and it also shows good cycling stability as well. Therefore, based on the above investigations, ordered mesoporous phenol–formaldehyde carbon such as C-FDU-16 can be a potential candidate for supercapacitors after the simply acid treatment.