The development course of jet engine is described. The engine which thrust weight ratio is about 8 is the power of the main fighters on active service in the developed countries. The 4th generation fighters stalling the jet engine with thrust weight ratio 10 will be gradually equipped with the army after 2003~2007, and will become the main fighting aircraft of USA and some western countries and even several neighbor countries and area of China after 2010. This paper sums up the development and key technologies of civil turbo\|fan engine and power of helicopter. The aero\|engine development will be confronted with new opportunities in the 21st century. The development direction of the main key technologies on the aircraft power in the 21st century is indicated.