The flux vector splitting method is adopted to solve the 2-D Euler equations and a numerical simulation is conducted for the division-flow inlet of Dual Combustor Ramjet (DCR) as well as the cold-mixing flow field of both flows from a dump combustor and from a supersonic inlet.The computational results provide a clear shock construction of the whole flow field and physical pictures of the two mixing high-speed streams in the supersonic combustor.The numerical results of the research can be available for reference to the ignition and combustion of the DCR.