Abstract: For cable-supported structures，prestress loss of cables has great influence on the structural bearing capacity and safety of the cable-supported structures． Factors of life cycle prestress losses in cable-supported structures were analyzed，including anchorage loss，batched tension loss，friction loss，relaxation loss，creep loss and temperature loss． Also，the calculation methods and compensation measures were stated in this paper． Prestress loss in the installation phase has a short-term effect，while prestress loss with time-varying effect in the normal usage phase has a long-term effect． The models of prestress losses in the two phases were established，and it was known with analysis of examples that the second sort of prestress loss should be considered in the design phase; and the first sort of prestress loss should be considered in the construction phase．