Abstract: In order to investigate the influence of test medium on the flow field and the performance of scramjet combustor, the cold and chemical non-equilibrium flow field in a Hyshot scramjet combustor has been simulated numerically by using the Favre-Averaged Navier-Stokes equations with the two-equation k-ω SST turbulence model. According to two test flow matching criterions and four airflow heating schemes, the effects of the inflow conditions are studied comparatively. The results indicate that:1) the burning fuel in the airflow upstream of the test chamber changes the composition and thermodynamic property of test medium; 2) the consistent condition of test mediums obtained by matching airflow total enthalpy is better than that obtained by matching airflow static temperature; 3) based on the two test flow matching criterions, the compositions and thermodynamic properties of the test medium obtained by burning methane (CH₄) and supplying oxygen (O₂) are consistent with each other, and the heating scheme can help reduce the correction of calculation or test results; 4) in the cases with the same test flow match condition, the flow parameters in the scramjet combustor simulated the basis of the entrance conditions with four different fueled combustion heating schemes show systematical difference; 5) regrding the combination parameters, the test flow matching criterions and heating schemes have more influence on the specific impulse than the Mach number and impulse function coefficient, and the impulse function coefficient can be used as a correlation parameter for the scramjet performance.