A reduced chemical kinetics model for typical combustion reaction systems is derived by means of the Computational Singular Perturbation (CSP) method.The combustion reaction governing equations are employed to construct ideal basis vectors,with them the coupling between the fast mode and the slow mode is decoupled properly.Several significant parameters are defined,such as the participation index,the radical pointer,and the importance index.Then the state equations of the fast modes and the reduced chemical kinetics model are obtained.A typical mixed combustion reaction system of CO-CH₄-Air is calculated,and the results show that the reduced combustion reaction system obtained by CSP method approximates the original system well.