In order to explore the chemical kinetics process of kerosene combustion in scramjet combustor, a detailed chemical reaction model for the combustion of RP-3 surrogate fuel was simplified to obtain a new reduced model (26 species and 89 reactions) based on the sensitivity analysis and reaction path analysis, and the combustion characteristics of supersonic reacting flow field were depicted. The ignition and combustion characteristics of this surrogate fuel under various conditions were simulated by using the reduced reaction model，and the simulation results were compared with the experimental data and the calculated results by the detailed reaction model. Furthermore, numerical simulations were implemented by using a coupled nonequilibrium reaction solver with the proposed reduced model, and the combustion characteristic of a scramjet combustor with single-side cavity was analyzed in detail. The results indicate that the reduced model can represent the ignition and combustion characteristic of the detailed model to some extent. And the proposed reduced chemical kinetic model predicts the myriad details of the reacting flow field accurately, including the distributions of major species, such as alkenes and cycloalkanes. At the same time, the number of species involved in the reduced model is much fewer, and the reduced model can improve the combustion simulation efficiency.