Acid Orange Ⅱ solution was degraded by gas-liquid gliding arc discharge，and its degradation kinetics and degradation mechanism were studied.The results showed that

when applied voltage was 10 kV，carrier gas was O2，gas flow rate was fixed at 0.4 m3·h-1，wastewater flow rate was 20 ml·min-1，shortest electrode distance was 3.5 mm，solution concentration was not more than 300 mg·L-1，the degradation reaction of Acid Orange Ⅱ by gliding arc discharge followed the first-order law.The absolute quantities of H2O2，O3 and the relative quantity of OH· produced by gliding arc discharge in distilled water were measured.The main intermediates were detected during decomposition，such as acetic acid，oxalic acid，malonic acid，phenol，3-hydroxyhypnone，naphthalene，benzene sulfonic acid，phthalic acid（anhydride），β-naphthalene etc. by ultraviolet-visible（UV-Vis）spectroscopy，ion chromatograph（IC）and gas chromatograph coupled with mass spectrophotometer（GC-MS）techniques.The possible degradation pathway of Acid Orange Ⅱ was also speculated，that was，hydroxyl radical reacted with the azo linkage-bearing carbon of naphthol-ring，and the C—N cleaved，the azo-dye decolored and mineralized.