Abstract: The transition processes of supersonic combustion in a dual-mode scramjet were investigated by means of directly-connected tests under the simulated conditions corresponding to the flying altitude of 25 km and the Mach number of 6. Pressure distribution on the wall of the combustor and one-dimensional simulation indicate that the combustion mode transition can be carried out by altering fuel injection position and equivalence ratio. Comparison of switch sequences of different fuel-injection position shows that the combustion mode changes are determined by the fuel distribution in a combustor, but the combustor has a certain ability to resist fuel disturbance.