To promote treatment efficiency of organic pollutant, an improved multi-anode contact glow discharge reactor was developed for dye discoloration. This paper investigated how and what extent multi-anode contact glow discharge electrolysis (m-CGDE) could improve the discoloration efficiency of Acid Orange 7 (AO). I-V characteristic of m-CGDE was also studied in details. It was found that the critical voltage of m-CGDE was same to that of single anode. The concentration of H2O2 in the anolyte and discoloration rates of AO increased with increasing treatment time and anode number. Furthermore, an improved m-CGDE reactor was designed by replacing platinum wire with stainless steel wire. Under the same conditions, multiple stainless steel anodes greatly enhanced the discoloration of AO. The trace amount of iron ion from stainless steel anodes played Fenton-like reaction important role. (C) 2011 Elsevier Ltd. All rights reserved.