The effect of initial CO₂ concentraion on NO destruction and regeneration was investigated as part of our ongoing research on NO emission from CO₂ recycled coal combustion, which could realize easy CO₂ recovery and drastic NO reduction simultaneously. Experiments were carried out in a flat flame burner for CH₄ / O₂ / Ar / NO / CO₂ flame at various excess oxygen ratios(from 0.6 to 1.2) and CO₂ concentrations(from 0% to 48%). It was found that CO₂ has a pronounced negative effect on the destruction of NO under fuel-rich condition. In contrast, under fuel-lean condition, the effect of CO₂ becomes smaller even at high CO₂ concentration. Kinetic Modeling showed that a large part of NO is regenerated through the reaction N+CO₂=NO+CO at high CO₂ concentrations. The effect of CO₂ is not so significant under fuel-lean condition because this reaction is no longer competitive with other NO formation reactions in this case.