The history, trend and existing difficulty of the modern reliability analysis theory of structural systems are briefly reviewed.Emphasis is laid on the attribution, -characteristics and applicable ranges of the FTA method and the, PLSA method used in the field of system reliability analysis and design. For the purpose of application, a discu'ssion is made on the detail reliability analysisand design method used for the structural design of aircraft, ship, pressure vesseland civil building. Based on the work...