High-content　polyurethane-modified　asphalt　exhibits　superior　high-temperature　performance　and　low-carbon　construction　advantages　but　suffers　from　compromised　low-temperature　flexibility.　This　work　introduces　dynamic　disulfide　bonds　into　high-content　polyurethane-modified　asphalt　by　replacing　conventional　chain　extenders　(4,4′-methylene-bis(2-chloroaniline))　with　aromatic　2,2′-diaminodiphenyl　disulfide　and　linear　3,3′-dithiodipropionic　acid　to　develop　a　more　durable　and　balanced-performance　modified　asphalt　material.　Mechanical　tensile　and　dynamic　shear　rheology　tests　identified　an　optimal　molar　substitution　ratio　of　16　%　for　dynamic　disulfide　bonds.　Subsequently,　the　effects　of　the　dynamic　disulfide　bonds　on　the　high-/low-temperature　rheological　properties　and　fatigue　resistance　of　modified　asphalt　were　investigated,　while　the　chemical　structure　and　thermodynamic　impacts　were　also　investigated　by　Fourier　transform　infrared　spectroscopy　and　differential　scanning　calorimetry　tests.　The　results　showed　that　the　introduction　of　dynamic　disulfide　bonds　increased　the　elongation　at　break　of　modified　asphalt　by　more　than　55　%,　despite　the　reduction　in　its　tensile　strength　and　complex　modulus,　while　effectively　maintaining　its　high-temperature　rutting　resistance.　And　multiple　stress　creep　recovery　tests　revealed　that　the　chain　extenders　containing　dynamic　disulfide　bond　can　well　maintain　the　high-temperature　permanent　deformation　resistance　and　deformation　recovery　ability　of　modified　asphalt.　Concurrently,　the　introduction　of　dynamic　disulfide　bonds　can　improve　its　low-temperature　entropy　elasticity　and　creep　performance　(32.3　%　increase　in　m-value),　significantly　enhance　its　low-temperature　cracking　resistance,　with　the　linear　3,3′-dithiodipropionic　acid　showing　superior　effectiveness　as　evidenced　by　the　lower　glass　transition　temperature.　Furthermore,　the　introduction　of　dynamic　disulfide　bonds　can　substantially　improve　the　maximum　strain　capacity　and　strain　energy　by　more　than　35　%,　while　the　fatigue　life　at　2.5　%　and　5.0　%　strain　levels　rose　by　more　than　39　%　and　31　%,　respectively,　with　the　linear　3,3′-dithiodipropionic　acid　exhibiting　superior　performance.　This　work　provides　novel　design　principles　and　theoretical　support　for　designing　durable　thermosetting　polyurethane-modified　asphalt　with　balanced　performance.　©　2025　Elsevier　Ltd