When the rocket works in some cases, shock wave may appear in rocket nozzle in RBCC engine. The shock wave is supposed to be a normal shock wave in the one-dimensional conceptual analysis model. The existence conditions and influences of the normal shock wave on performance of RBCC dynamical system were analyzed. The results indicate that the lower the total pressure is in rocket combustion chamber or the higher the flight Mach number is, the easier the normal shock wave appearances in the nozzle. The generation of the normal shock wave in rocket nozzle has a certain influence on the ejector performance of RBCC dynamical system.