Abstract: The investigation of core engine and derivative aero-engine development was presented.The increase in engine thrust can be realized by increasing air flow or cycle power of the core engine.But the margin of rotor speed,flow capacity and power needed of the turbomachinery should be considered early in the design stage.Serial development based on the core engine can be done by keeping the corrected speed of the high-pressure compressor constant,or keeping the maximum gas temperature constant.In practice,both of the foregoing approaches were adopted.Therefore,the margin of the maximum gas temperature,rotor speed and capability of HP compressor are required during the development of core engine and baseline aero-engine.However,the approaches in developing high bypass ratio engine and low bypass ratio engine are different.