Degradation of diuron in aqueous solution by gas-liquid hybrid discharge was investigated for the first time. The effect of output power intensity, pH value, Fe2+ concentration, Cu2+ concentration, initial conductivity and air flow rate on the degradation efficiency of diuron was examined. The results showed that the degradation efficiency of diuron increased with increasing output power intensity and increased with decreasing pH values. in the presence of Fe2+, the degradation efficiency of diuron increased with increasing Fe2+ concentration. The degradation efficiency of diuron was decreased during the first 4 min and increased during the last 10 min with adding of Cu2+. Decreasing the initial conductivity and increasing the air flow rate were favorable for the degradation of diuron. Degradation of diuron by gas-liquid hybrid discharge fitted first-order kinetics. The pH value of the solution decreased during the reaction process. Total organic carbon removal rate increased in the presence of Fe2+ or Cu2+. The generated Cl-1, NH4+, NO3-, oxalic acid, acetic acid and formic acid during the degradation process were also detected. Based on the detected Cl-1 and other intermediates, a possible degradation pathway of diuron was proposed. (C) 2008 Elsevier B.V. All rights reserved.