Abstract: The cycle parameters of ATF propulsion with or without supersonic cruise missions have been optimized respectively and compared.And the effects of supersonic cruise range,engine life cycle cost and engine part efficiencies on the optimization of the engine cycle parameters have been researched.The results show that a turbofan engine with a small bypass ratio must be installed,and a suitable turbine entry temperature is obtained by optimization with life cycle cost.The enhancement of the engine part efficiencies has influence on the optimization of the cycle and the aircraft markedly raises the aircraft performance.The afterburner temperature must be taken very high due to the limit of the engine maximum diameter.