Abstract: Using strong ionization discharge method,a majority of gas molecules in the air such as O2,N2 and H2O are ionized and made into OH· of high concentration.Under the condition of high temperature,non-catalyst and non-absorbent,SO2 is directly oxidized into fogdrops of H2SO4 in plasma reactor,and then is collected as an important resource in electric precipitator.In the experiment,the effect of the changes of reaction time in plasma reactor on desulfurizing efficiency under the condition of different SO2 primary concentration,water content and reduced electric field intensity is studied.Experimental data show that desulfurizing is fast by this method.When SO2 primary concentration,water content and reduced electric field intensity are respectively 850×10-6,3.6% and 370 Td,desulfurizing efficiency can attain to 88.4% in about 0.74 s.