The interaction between De-NO and De-SO2 from flue gas in a pulsed corona discharge plasma (PCDP) reactor was studied experimentally. A mechanism and kinetic scheme of De-NO and De-SO2 inside the PCDP reactor has been proposed and verified by comparison of the simulated and experimental results. The dominant radicals and elementary reactions are confirmed through sensitivity analysis. It has been found that there is significant interaction between the De-NO and De-SO2 processes in a PCDP reactor, and that the De-NO reactions prevail over the De-SO2 ones. The interaction consists of competitive reactions between NO and SO2 involving oxidative radicals, as well as interaction reactions between NO, SO2 and their derivatives. Through sensitivity analysis it has been found that the most effective elemental reaction to De-NO is NO + HO2 < = > OH + NO2 and that the most helpful radical is HO2. The most effective reaction for De-SO2 is SO2 + O < = > SO3 and the most helpful radical is atomic O. The study reveals the interaction mechanism between De-NO and De-SO2 in PCDP and provides a theoretical basis to improve the performance of simultaneous NO and SO2 abatement in a PCDP reactor.