In recent years, with the rapid development of electric and electronic technology, the All-Electric Aircraft (AEA) concept has attracted more and more attention, which only utilizes the electric power instead of conventional hydraulic and pneumatic power to supply all the airframe systems. To meet the power requirements under various flight stages and operating conditions, the AEA approach has resulted in the current aircraft electrical power generation capacity up to 1.6 MW. To satisfy the power quality and stability requirements, the advanced power electronic interfaces and more efficient power distribution systems must be investigated. Moreover, with the purpose of taking the full advantages of available electrical power, novel dynamic power distribution management research and design for an AEA must be carried out. The main objective of this thesis is to investigate and develop a methodology of more efficient power distribution management with the purpose of minimizing the rated power generating capacity and the mass of the electrical power system (EPS) including the power generation system and the power distribution system in an AEA. It is important to analyse and compare the subsistent electrical power distribution management approaches in current aircraft. Therefore the electrical power systems of A320 and B777, especially the power management system, will be discussed in this thesis. Most importantly the baseline aircraft, the Flying Crane is the outcome of the group design project. The whole project began in March 2008, and ended in September 2010, including three stages: conceptual design, preliminary design and detailed design. The dynamic power distribution management research is based on the power distribution system of the Flying Crane. The main task of the investigation is to analyse and manage the power usage among and inside typical airframe systems by using dynamic power distribution management method. The characteristics and operation process of these systems will be investigated in detail and thoroughly. By using the method of dynamic power distribution management, all the electrical consumers and sub-systems powered by electricity are managed effectively. The performance of an aircraft can be improved by reducing the peak load requirement on board. Furthermore, the electrical system architecture, distributed power distribution system and the dynamic power distribution management system for AEA are presented. Finally, the mass of the whole electrical power system is estimated and analysed carefully.