The decomposition of aniline in supercritical water (SCW) was studied. Experiments were performed at various temperatures, pressures, residence times, dosage of oxidant H2O2 and initial aniline concentrations to investigate their effect on the destruction efficiency. Manganous sulfate and ferrous sulfate were screened out during the experiment to study the effect of the homogenous catalysts on destruction efficiency. The effect of pH was also studied. The experiments showed that the dosage of oxidant H2O2, experimental temperature, pressure, reaction residence time and even initial concentration of the aniline in wastewater have a significant affect on the TOC removal; manganous sulfate and ferrous sulfate improve the oxidation; TOC removal improves slightly with a decrease in the initial pH value. At a system temperature 450degreesC, pressure 28 MPa, initial pH 4.0, residence time 46 s and K value 1.1, TOC removal can reach 100%. (C) 2002 Elsevier Science B.V. All rights reserved.