The is paper employed the stage critical strength-considered branch-bound method to explore the major failure mode of a cable-stayed bridge,and investigated the variations of major failure mode and system reliability in the cases of cable breakage and resistance deterioration.The study indicates that,in the case of without cable breakage,the correlation among the major failure modes of the structure is high,while the correlation appears to clear grouping characteristics in the case of a sudden failure of a cable.The system reliability decreased with the resistance deterioration of the cable.Moreover,the remaining structural system reliability indices decreased remarkably in the case of the breakage of the outside cable,and the dominant cable that has the greatest impact on the system reliability was captured to guide the further structural design.