The commercial production of 2-nitro-4-methylsulphonylbenzoic acid (NMSBA) is oxidizing 2-nitro-4-methylsulphonyltoluene (NMST) by nitric acid catalyzed with V2O5. A heterogeneous catalytic system composed of phosphotungstic acid supported on activated carbon, Co, Mn, and Br is used to catalyze the production of NMSBA from NMST by oxygen in this paper. The experiments show that the heterogeneous catalytic system composed of HPW@C, Co, Mn, and Br is capable of speeding up the oxidation of NMST to NMSBA by oxygen and acquiring a higher NMST oxidation rate and NMSBA yield than the homogeneous H3PW12O40/Co/Mn/Br catalytic system. The best HPW@C catalyst is obtained by supporting 0.0125 g/g H3PW12O40 on carbon followed by being calcined at 220 degrees C for 4 h under nitrogen atmosphere. The best heterogeneous catalytic system consists of 2.38 x 10(-3) g/g HPW@C, 925 ppm Br, 236 ppm cobalt, and a Mn/Co molar ratio of 2.5. The usage of phosphotungstic acid in the heterogeneous system is diminished substantially.