Abstract: Taking surplus sludge of urban sewage as raw material, different methods were used to prepare adsorbent for flue gas desulfurization. The factors affecting the desulphurization efficiency for the systems of SO2—O2—N2 and SO2—O2—H2O(g)—N2 were discussed, and a stationary bed model for the system SO2—O2—H2O(g) —N2 was also established. The results indicated that the adsorbent prepared by pyrolysis was better. In comparison with commodity activated carbon, the adsorption capabilities of the adsorbent made from surplus sludge were studied. The best absorption conditions for two adsorption systems were determined, and the simulated values with the stationary bed model and experiment values were in good agreement.