Abstract: Following the gradual unification of aircraft secondary power into electrical power, the electrification of aircraft propulsion power is an important trend and advanced stage of the development of aviation electrification. The electrified propulsion system can significantly improve the energy conversion efficiency, and it is a promising way for the green development of the aviation industry. The electric machine system is the core electromechanical energy conversion link of the aircraft electric propulsion system. High performance electric machine and power electronics technologies are basic support for the development of electric propulsion aircraft. Based on the aircraft power system architectures, the characteristics and requirements of the electric machine system for electric propulsion aircraft are analyzed first. The application and research status of permanent magnet synchronous machine, asynchronous machine, wound-rotor synchronous machine and superconducting machine in electric propulsion aircraft are summarized, and the key technologies of different types of electric machines and drives are systematically discussed. Furthermore, the key technologies of different types of electric machine and power electronics converter are also summarized. Finally, the promotion of new technologies on the development of electric machine system on electric propulsion aircraft is prospected, including new materials, new devices, new processes and artificial intelligence.