Catalytic oxidation of NO followed by simultaneous removal of SO2 and NOX with ammonia is a promising method for control of coal-fired flue gas pollutants. We investigated simultaneous absorption of SO2 and NOX in a packed column with ammonia, and found that SO2 and NOX could promote absorption with each other in the process of simultaneous removal SO2 and NOX. The removal efficiency of SO2 and NOX was, respectively, about 98% and 70.9% at pH 5.5, temperature 323.15 K, SO2 concentration 1,800×10^(-6), NOX concentration 400×10^(-6) and mNO2/mNO 1 in our experimental system. The experimental results also show that the formation of sulfite oxidized by reacting with dissolved NO2 and the molar ratio of sulfite to total sulfur is more than 0.8 in the solution. Accordingly, the energy consumption for sulfite oxidation would be greatly reduced in the process of simultaneous desulfurization and denitrification with ammonia.