The design and synthesis of nitrogen-rich activated carbon materials has been seen as one of major topic for supercapacitors. Herein, porous activated carbon nitride (ACN) materials were obtained by a one-step pyrolysis/activation of melamine and citric acid derived precursor at different temperature. The nitrogen/oxygen content and BET surface area of ACNs were varied with the increasing of pyrolysis temperature. In detail, the optimized ACN-700 electrode with a BET surface area of 716 m(2) g(-1) show a specific capacitance of 185 F g(-1) at the current density of 0.5 A g(-1). Then, the assembled symmetric cell based on ACN-700 can achieve the energy density of 16.9 Wh kg(-1) and 6.2 Wh kg(-1) in 2 M [BMIm]BF4/acetonitrile and 6 M KOH, respectively. The enhanced performance of ACN-700 is mainly due to the introducing of nitrogen derived pseudo-capacitance, associated with the large surface area and surface oxygenation after activation. Thus, the raw materials, facile procedure and high performances enable the current activated carbon nitride material with great potentials for supercapacitors.