To improve the production efficiency of H2O2 in Electro-Fenton system, the nitrogen functionalized carbon nanotube (NCNT) electrode was prepared. NCNT was obtained by nitrogen functionalization of carbon nanotube (CNT) by pulsed high voltage discharge in a gas-liquid hybrid reactor. It was found that nitrogen functionalities were pyridine, pyrrol and quaternary species. H2O2 formation rate on the CNT electrode was greatly improved by the presence of nitrogen functionalities due to the acceleration of electron transfer of O-2 reduction. For the Electro-Fenton degradation of methyl orange, the NCNT electrode showed faster removal of methyl orange when compared to the CNT electrode. The repeatability test suggested that the stability of the NCNT electrode was very good. NCNT is a promising cathode material for the Electro-Fenton system. (C) 2008 Elsevier B.V. All rights reserved.