The oxidation of ammonium sulfite in the ammonia-based flue gas desulfurization (FGD)process was investigated in a multi-needle-to-plate gas phase pulsed corona discharge reactor in this paper.The effect of several parameters,including capacitance and peak pulse voltage of discharge system,electrode gap and bubbling gas flow rate on the oxidation rate of ammonium sulfite was reviewed.The experimental results indicate that the gas phase pulsed discharge system with a multi-needle-to-plate electrode can oxide the ammonium sulfite efficiently.The oxidation rate increased with the applied capacitance and peak pulse voltage and decreased with the electrode gap.As the bubbling gas flow rate increased,the oxidation rate increased first and then tended to reach a stationary value.These results would be important for the process optimization of the(NH4)2SO3 to(NH4)2SO4 oxidation.