To find out a new dry-type desulfurization process with high efficiency and cost performance, a hybrid-type reaction process combining pulsed streamer corona plasma and TiO2 catalyst was developed in order to oxidize SO2 to SO3. Experiments of both gas-phase reaction and surface reaction were performed to elucidate oxidation characteristics. Experimental results show that the oxidation fraction Of SO2 to SO3 in the gas-phase reaction is below 5% at low temperatures (under 800 K). Similarly, when using TiO2 only as catalyst and applying the pulsed streamer corona plasma, respectively, the oxidation fraction is not increased significantly. Moreover, when simply combining the gas-phase reaction and the surface reaction, the oxidation fraction can. reach and maintain only about 10% below 673 K. Contrary to the above two results, the oxidation fraction could-be increased significantly by adding H2O of about 0.2 vol %. Hydrogen peroxide was: demonstrated to have-better oxidation promotion characteristics in comparison to the addition of H2O and H2O + plasma. The oxidation fractions of 66% and 90% can be achieved, respectively, by adding a very small amount of H2O2 and applying the pulsed streamer corona plasma in the reaction process. Finally, these experimental results confirmed our initial hypothesis that hydroxyl radicals (OH) enhance: the oxidation Of SO2 to SO3 in both the gas-phase reaction and the surface TiO2.