The chemical kinetics associated with plasma-assisted oxidation of methane are investigated numerically. The model was developed by expanding the existing model that describes the chemical processes induced by plasma in a H2/O2/Ar mixture. To support the model development, experiments wer performed using a plasma flow reactor in which the fuel oxidation proceeds with the aid of plasma discharges. The mixtures used were heavily diluted with argon in order to study the reactions in temperature-controlled environments by suppressing the temperature changes induced by chemical reaction. The temperature of the reactor was carried between 420 K and 1250 K, and the pressure was fixed at 1 atm. Simulations were performed for the conditions corresponding to the experiments to allow direct comparison. The overall trends of numerical and experimental results agree well across the temperature range considered. The reaction paths resposnsible for fuel oxidation and the formation of stable minor species at different temperatures are identified.