The effect of NO on methane oxidation in O-2/NO combustion atmosphere was investigated using reactive molecular dynamics (RMD) calculations. It has been observed that, the conversion of NO could accelerate the oxidation of CH4. To provide a detailed description for this phenomenon, the corresponding kinetic behavior of nitrogen-containing compounds were systematically analyzed at atomistic level. It revealed that NO presented a two-fold impact with respect to CH4 oxidation, on one hand, the presence of NO enhanced CH4 consumption by converting HO2 into OH radical; on the other hand, the appearance of NO inhibited CH4 consumption by catalyzing chain-carrier recombination reaction.