While　the　current　seismic　fortification　standards　for　cable-stayed　bridges　have　been　established,　determining　the　return　periods　and　fortification　objectives　remains　insufficient.　This　study　introduces　a　multi-level　seismic　fortification　objective　for　cable-stayed　bridges　with　safe-belt　devices.　The　safe-belt　device　protects　the　primary　components　and　enables　transfers　to　the　restraint　system　based　on　varying　seismic　requirements.　For　this　investigation,　a　double-tower　cable-stayed　bridge　was　chosen　as　the　case　study.　Three　finite　element　models　with　varying　structural　configurations　were　developed.　Subsequently,　an　elastoplastic　time-history　analysis　was　performed　under　four　levels　of　seismic　excitation　across　different　site　categories.　The　results　indicate　that　the　primary　structures　of　traditional　cable-stayed　bridges,　specifically　the　towers　and　lower　crossbeams,　are　vulnerable　to　severe　damage　during　extremely　rare　earthquakes.　Incorporating　safe-belt　devices　in　a　doubletower　cable-stayed　bridge　effectively　reduces　the　internal　forces　exerted　on　the　primary　structures　by　utilizing　the　combined　action　of　the　dual　towers,　thereby　preventing　severe　damage.　Additionally,　these　devices　allow　for　controlled　girder-end　displacement　until　their　capacity　is　reached.　This　double-tower　cable-stayed　bridge　successfully　meets　the　multi-level　seismic　fortification　objectives　and　satisfies　the　performance　requirements　at　each　level.