Harness integration is very important in EWIS（Electrical Wiring Interconnection Systems） design procedure, and is also the base of detailed design. The purpose of harness integration is that which system wires could be bundled in the same harness. Harness integration can reduce the number of harness, and is also easy for manufacture, configuration management and installation. The design method of harness integration is to integrate the wires in the electrical schematic diagram into the preliminary harness according to the system requirement, then integrate them according to the aircraft zones, and finally integrate them into the final harness on aircraft.