The prognostics and health management (PHM) system is now playing an important role in promoting transition of the operational aircraft from run-to-failure, scheduled preventive maintenance to condition-based maintenance. Considering technique characteristics and maintenance demand of the new generation operational aircraft, three different backup blue prints of on-board prognostics and health management system architectures are contrasted, and then a layered architecture is presented, which include vehicle level PHM, area level PHM, subsystem level PHM and module / component PHM. Finally, the division of hierarchy, function description of elements, information transmission and external logic are discussed.