In order to provide the basis to efficiently reduce the energy consumption and improve the removal rate, the simultaneous removal processes of SO2 and NO in two pulsed discharge plasma systems (NO/SO2/N-2/O-2/H2O and NO/SO2/N-2/O-2) were simulated respectively, and then the removal characteristics of these two gas systems were analyzed. The results show that NO can be completely removed when the residence time is close to 1.3 s and SO2 removal rate is 61.5% when the residence time reaches 3 s in a system containing water vapor. When the system does not contain water vapor, NO removal rate is still much high, while SO2 removal rate is approximately zero, and its concentration is below 1x10(-6) at all levels of O-2 concentration. When the system contains water vapor and the residence time reaches 3 s, the concentrations of HNO3, HNO2, N2O and N2O5 are 102x10(-6), 15x10(-6), 35x10(-6) and 19x10(-6), respectively, while HSO3 concentration is approximately zero throughout the entire process and the removed SO2 is converted to H2SO4 completely. HO2 concentration is very small during the process. After NO is removed completely, H2O2 concentration rises from zero to 16x10(-6) at the end of the process. When the system does not contain water vapor, trends of change in the concentrations of NO, NO2, N2O5 and N2O are almost the same as those in a system containing water vapor. When O-2 concentration is increased, NO removal velocity will be faster and the peak of the concentration curve of NO2 will be higher. NO removing velocity is much faster in a system containing water vapor than that in a system without water vapor when both systems have almost the same O-2 concentration.