To　enhance　both　the　utilization　efficiency　of　solid　waste　coal　gangue　and　the　overall　performance　of　asphalt　materials,　hexamethylene　diisocyanate　(HDI)　was　employed　to　organically　modify　coal　gangue　powder　(CGP)　so　as　to　prepare　organic　coal　gangue　powder　with　terminal　active　isocyanate　groups　(HDI-CGP).　The　structure,　particle　size　and　micro　morphology　of　HDI-CGP　were　characterized　and　tested.　The　influence　of　HDI-CGP　on　the　physical　properties,　rheological　properties,　aging　properties,　and　road　performance　of　asphalt　materials　was　investigated.　Comparative　analysis　was　made　using　octadecyl　isocyanates　(ODI,　a　monoisocyanate)　modified　CGP　(ODI-CGP).　The　results　confirmed　successful　preparation　of　HDI-CGP　and　ODI-CGP　without　damaging　the　crystal　structure　of　coal　gangue.　HDI-CGP　and　ODI-CGP　exhibited　reduced　agglomeration　and　particle　size　compared　to　unmodified　CGP.　The　compatibility　and　stability　of　both　HDI-CGP　and　ODI-CGP　with　asphalt　were　superior　to　that　of　CGP.　HDI-CGP,　specifically,　interacted　with　active　groups　in　asphalt,　generating　liked　cross-linked　structures.　HDI-CGP　was　more　efficacious　in　bolstering　the　high-temperature　stability　of　asphalt　(evidenced　by　higher　softening　point,　complex　modulus　at　30–80°C,　and　rutting　resistance),　while　minimally　affecting　low-temperature　properties,　such　as　low-temperature　ductility　and　bending　creep　performance.　HDI-CGP　also　enhanced　aging　resistance　of　asphalt　binder　and　optimized　rutting,　cracking,　and　moisture　damage　resistance　of　asphalt　mixture　compared　to　CGP　and　ODI-CGP.　©　2025　Elsevier　Ltd