Abstract: Chemkin II package and the existing experimental data on methaneethane-propane mixture oxidation are employed for evaluating the performance of three detailed reaction mechanisms (GRI-3.0 mechanism, Konnov-0.5 mechanism, and Petersen-C5 mechanism) at high pressure, intermediate temperatures. It is found that the prediction results of GRI-3.0 mechanism agree with the ignition delay time well for a wide range of pressure and fuel ratio, hence, the GRI-3.0 model is suitable for the modeling and simulation of noncatalytic partial oxidation of methane under high pressures and temperatures.