The　poor　adhesion　of　asphalt-granite　limits　the　application　of　granite.　This　research　aims　to　enhance　the　adhesion　of　asphalt　and　granite　by　establishing　chemical　connections　between　the　hydroxyl　groups　on　granite　surface　and　the　incompletely　reacted　isocyanate　groups　in　polyurethane　(PU)　modified　asphalt.　For　this　purpose,　end-capped　PU　modified　asphalt　(PUMA)　was　prepared,　the　adhesion　mechanism　between　PUMA　and　granite　was　analyzed　by　Raman　spectroscopy,　the　adhesion　properties　between　PUMA　and　granite　at　different　curing　periods　were　evaluated　by　boiling　and　pull-out　tests,　and　the　wettability　of　PUMA　on　granite　and　its　moisture　sensitivity　were　evaluated　using　surface　free　energy　(SFE)　method.　The　findings　suggested　that　the　incompletely　reacted　isocyanate　groups　in　PUMA　can　establish　a　chemical　connection　with　the　hydroxyl　groups　on　the　surface　of　granite.　The　adhesion　between　asphalt　and　granite　can　be　greatly　improved　by　the　addition　of　PU,　and　this　improvement　is　amplified　as　the　curing　time　is　extended.　When　the　curing　time　is　extended　to　3　days,　the　fracture　mode　between　asphalt　and　granite　changed　from　adhesive　failure　to　cohesive　failure,　and　after　15　days　of　curing,　the　coating　ratio　of　PUMA　on　granite　following　the　water　boiling　test　can　be　raised　by　28.11%　in　comparison　to　the　base　asphalt.　The　water　damage　resistance　of　PUMA-granite　system　can　be　increased　by　adding　PU　and　the　adhesion　work　and　combination　ratio　of　the　freshly　prepared　PUMA　were　increased　by　55.91%　and　79.45%,　respectively,　as　compared　to　base　asphalt.　This　study　has　great　significance　for　enhancing　the　adhesion　between　asphalt　and　granite　and　encouraging　granite　application.　©　2024　American　Society　of　Civil　Engineers.