The adsorption capacity and release behavior of sulfamethoxazole (SMZ) were determined on three types of activated carbon: AC-0 (commercial activated carbon), AC-Fe (activated carbon/iron oxide composites) and AC-Mn (activated carbon/manganese oxide composites). The adsorption fitted to the Freundlich, Langmuir and Langmuir-Freundlich models. The Langmuir-Freundlich model had been found most suitable for equilibrium data. The presence of iron oxide and manganese oxide did not significantly affect the surface area or pore structure of activated carbon, in addition, which had little effect on the adsorption capacity of activated carbon. Compared to AC-Fe and AC-Mn, AC-0 had a higher efficiency of SMZ desorption. Adsorption probably occurred through a surface complexation mechanism and was accompanied by degradation of some SMZ, which would play significant role in improving the ability of AC-Fe and AC-Mn adsorbing SMZ.