Catalytic oxidation of NO at low temperature is a potentially competitive method, and the catalyst's preparation and modification are crucial for NO catalytic oxidation. Non-thermal plasma surface treatment (NTPST) has been applied to manganese oxide (MnOx) catalysts for catalytic oxidation of nitrogen oxide (NO) in the presence of O-2. The plasma-treated MnOx catalyst presents excellent low-temperature catalytic activity in the process of NO oxidation. And the NO conversion was 79% at 125 degrees C with a space velocity of 30,600 h(-1). To clarify the plasma effect, the catalysts were characterized by XRD, SEM and EDS. The enhanced performance of MnOx catalysts as pretreated by plasma was ascribed to two effects: (1) the etching and sputtering on catalyst's surface with the treatment of plasma can improve the dispersion of catalysts; (2) EDS results revealed that the NTPST could increase the K and O content on the catalyst's surface which contributed to a higher activity for NO catalytic oxidation. It demonstrates that the NTPST is an effective way to pretreat catalyst for NO removal. (C) 2012 Elsevier B.V. All rights reserved.