Treatment of high-concentration wastewater from a chemical company by wet air oxidation (WAO) is studied. Experiments were conducted to investigate the effects of the operating pressure and temperature on the chemical oxygen demand (COD) removal. Both air and oxygen were employed as the oxygen supply for the WAO treatment process. Catalytic effects of copper sulfate, cobalt oxide, and zinc oxide on the WAO efficiency were also examined. It was found that over 50% of COD removal can be easily realized in an hour of WAO oxidation. Two kinetic models (first-order and generalized) were employed to represent the experimental data, and their fit to those experimental data was compared. The rate coefficients and the kinetic parameters of the two models were determined also.