N-doped carbon material is a kind of promising oxygen reduction reaction（ORR） electrocatalyst.Two kinds of N-doped Ketjenblacks carbon were prepared using urea and melamine as nitrogen sources by a high temperature calcination method under nitrogen atmosphere.The structure and morphology of the Ketjenblacks carbon materials being doped by N before and after were characterized by X-ray diffraction（XRD），X-ray photoelectron spectroscopy（XPS），field emission scan ning electron microscope（FESEM） and specific surface area analysis techniques.Results showed that the N-doped Ketjen black maintained graphite structure，the morphology and BET surface area were not changed significantly.The XPS charac terization illustrated that nitrogen was introduce to the N-doped Ketjenblack carbon.Using melamine as nitrogen source could introduce more pyridinic N than that of using urea.Cyclic voltammetry and linear sweep voltammetry were used to investigate the electrocatalytic oxygen reduction performance of three samples.The results showed that doping nitrogen on Ketjenblack carbon could enhance the electrocatalytic oxygen reduction performance effectively.For the pristine Kenjenblack carbon，the halfwave potential were 0.746 V.After using urea and melamine as nitrogen sources，the halfwave potential for urea-N/AC and melamine-N/AC were enhanced to 0.756 V and 0.786 V，respectively.