The stripping-adsorption process was used to treat the high concentration of ammonia nitrogen in the desulfurization wastewater. The results of trial operation showed that when the influent flowrate was 95.8 m3/d,pH was 10~11 and water temperature was 35~45 ℃, the concentration of ammonia nitrogen in the effluent was 40.3~150.4 mg/L which met the requirements of discharge standard of wastewater from limestone-gypsum flue gas desulfurization system in fossil fuel power plants (DL/T 997—2006). The removal rate of ammonia nitrogen was 90%~96.54%. The treatment cost was 14.84 yuan/ton.