Nitrogen-doped porous carbon materials(NPCs) have been successfully fabricated by a simple one-step pyrolysis of diethylenetriaminepentaacetic acid(DTPA) in the presence of KOH. The as-synthesized NPCs displayed a high specific surface area(3214 m^2 g^(-1)) and a well-defined porous structure when the annealing temperature reached 800 ℃, which showed superior electrochemical performance as supercapacitor electrode materials. Electrochemical tests showed that the NPCs achieved an impressive specific capacitance of 323 F g^(-1) at a current density of 0.5 A g^(-1) in 6 M KOH aqueous solution and an outstanding cycle stability, negligible specific capacitance decay after 5000 cycles at 10 A g^(-1). This strategy offered a new insight into the preparation of novel carbon materials for the advanced energy storage devices, such as supercapacitors, fuel cells and lithium ion batteries.