A quasi-one-dimensional combustor model is developed using MacCormack’s method to solve simplified Navier–Stokes equations for the intention of simulating the flow parameters in the combustor. The combustor model is capable of predicting the flowfield of scramjet combustor. The Eckert reference technique is adopted in the heat transfer model of the regenerative cooling system. With these two models, the relationships between phenomena are investigated. Simulation results indicate that this coupled model of combustor and regenerative cooling system can be used to investigate the influence of the cooling channel geometry, flight Mach number and fuel equivalence ratio. This coupled model is useful for the pre-design of scramjet engines.