In the first part of this research, a detailed experimental study was conducted for the partial oxidation of methane (POM) over La2O3. It was shown that the interactions between gas-phase and surface reactions should be considered and that the POM is a homogeneous-heterogeneous reaction. In this second part of the study, a detailed mechanism is proposed that involves 450 elementary homogeneous reaction steps and 33 heterogeneous reactions. From this mechanism, simulations were performed using Chemkin software packages. Computed values are consistent with experimental results over a large range of temperatures (650-850 degrees C), residence times (0.7-6 s), and catalyst amounts (0.45-3.6 g).