In order to solve the numerical stiffness problem in the combustion of pyrolysis products of phenolic resin numerical simulation resulting from adopting the detailed chemical kinetic mechanism, the mechanism reduction were studied and acquired the optimal reduction with least accuracy loss. The perfect stirred reactor (PSR) model in Chemkin-Pro was chosen to study the detailed mechanisms of the mixture of methane and hydrogen consisting of 53 species and 325 elementary reactions with sensitivity analysis coupling with rate of production analysis. The mechanism was finally reduced to 15 species and 15 elementary reactions. The result showed that the reduced mechanism could sufficiently exhibit the characteristics of the detailed mechanisms and greatly reduced the computational cost and be used in the computational fluid dynamics (CFD) of the ejector perturbation of pyrolysis products of phenolic resin and the interactions with boundary layer.