Electrical power distribution network over current protection analysis is one of the important analyses for verifying the rationality, reliability and safety of the aircraft electrical power distribution network design. Over current protection analysis methods for aircraft electrical power distribution network is discussed in this paper. And a characteristic curve method is then presented. The characteristic curve method is based on the load current curve of the wire and the over current protection curve of the protection devices. The characteristic curve method is simple and practical. It can be used to verify the design of aircraft electrical power distribution network for certification.