Abstract: A systematie testing of unsteady state oxidation of low content SO_2 by periodic flow reversa1 was carried out in a bench-scale reactor packed with 4.58 L domestic commercial vanadium supported catalyst,S108.The effects of SO_2 content in feed,superficial velocity of gas,preheated temperature of the catalyst bed and operation period on transient temperature profiles and its peak values,time-average conversions and the propagation velocities of the thermal wave were observed.It was shown that periodic flow reversal of fixed-bed catalytic reactor certainly had considerable advantage of conventional steadystate operation especially for reversible exothermic reaction with low content reactant.The results obtained in this investigation would be used to compare with those predicted by mathematical model and to identify the global kinetic parameters in the best-fit model.