Ignition delay times of N2O/CH4/O-2/Ar mixtures with varying N2O mixing ratios (N2O/CH4 mole blending ratio = 0:100, 30:70, 50:50, and 70:30) were measured behind reflected shock waves at pressures of 1.2-16 atm, equivalence ratios of 0.5-2.0, and temperatures of 1220-2336 K. At currently investigated conditions; the reactivity of methane is significantly promoted by N2O addition, resulting in an obvious reduction of the ignition delay time, and this effect becomes more pronounced at the fuel-rich condition and high pressure. However, N2O addition only results in a slight reduction in the global activation energy. To eliminate the effect of different hydrocarbon mechanisms, a widely accepted kinetic mechanism, Aramco Mech 1.3, is used to combine with three available NOx submodels (Gersen et al., Konnov, and Mathieu et al.) and simulate the measured ignition delay times. Generally, the three assembled models give a similar prediction performance and agree well with the experimental- data for a low level of N2O addition, but they exhibit a discrepancy for a high level of N2O addition. Sensitivity analysis and radical pool analysis are conducted to interpret the kinetic effect of N2O addition on methane ignition chemistry. Results indicate that the promoting effect of N2O addition on methane ignition is mainly attributed to the contribution of the following three reactions: N2O + M = N-2 + O-center dot center dot + M, N2O + H-center dot = N-2 + (OH)-O-center dot, and N2O + (CH3)-C-center dot = CH3O center dot + N-2; which can significantly increase the concentration of the radical pool and accelerate the peak of the radical pool.