A novel advanced oxidation process-wet electrocatalytic oxidation(WEO)was studied with p-nitrophenol as model pollutant and β-PbO2 electrode as the anode.Compared with the effect of the individual wet air oxidation(WAO)and electrochemical oxidation(EO),the effect of WEO showed synergistic effect on COD removal under the conditions of temperature 160℃,C=1000mg·L-1,PN2=0.50MPa,Po2=0.9 MPa,current density=3 mA·cm-2,Na2SO4 3 g·L-1.And the synergistic factor got the best value of 0.98 within 120 min after 180 min treatment.The synergistic factor was studied after 120 min treatment at 100℃,120℃,140℃and 160℃,and the effect of 120℃was the best with the value of 1.26.Possible mechanism for the synergistic effect was discussed based on the analysis of free-radical generation and intermediates detected by HPLC and GC/MS.