The oxidation degradation of orange G (OG) in aqueous solutions by the activated carbon catalyzed peroxydisulfate (PDS) has been kinetically investigated. These processes are based on the generation of sulfate radicals, which are powerful oxidizing species found in nature. The results demonstrated that OG could be degraded by GAC/PDS reagent effectively. Moreover, the dosage of PDS and GAC, temperature and initial concentration of OG had an impact on OG oxidation, higher temperature and GAC dosage resulted in higher OG degrading rates. In addition, the empirical kinetic equation for OG oxidation by GAC/PDS combined system under the conditions of 0.050-0.125 mmol x L(-1) of OG, 5.0 of pH, 10/1-160/1 of n(PDS)/n(OG), 0.1-1.6 g x L(-1) of GAC, 298-338 K of temperature, could be reasonably represented by the first order kinetics, which was fitted very well with the experimental data. In addition, the catalytic properties of reused GAC have been investigated.