The characteristics of aircraft power supply are discussed from the aspects of nonlinear electric equipments in more electric aircraft, and the shortcoming of variable-frequency（VF）AC power systems is analyzed. Then, the importance of high temperature power electronic devices on the development of the aircraft power supply, distribution and electric equipments is given. The necessity of energy management and thermal management is outlined, as well as the new research direction of main electromechanical devices for the next generation more electric aircraft.Development of power electronics technology and its appratus is essential to the realization of more electri aircraft.