The　interfacial　interaction　between　asphalt　binder　and　mineral　aggregate　makes　different　components　have　different　diffusion　behavior.　It　influences　the　performance　of　interface　and　consequently　that　of　the　mix.　In　this　research,　the　models　of　four　asphalt　components　(asphaltene,　resin,　aromatics　and　saturate)　and　five　minerals　were　constructed　individually,　and　then　the　Al2O3-asphalt　interface　model　was　constructed　by　adding　the　asphalt　layer　and　mineral　layer　together.　The　interfacial　behavior　at　molecular　scale　was　simulated　by　setting　boundary　conditions,　optimizing　the　structure　and　canonical　ensemble.　The　mean　square　displacement　(MSD)　and　diffusion　coefficient　of　particles　were　selected　as　indicators　to　study　the　diffusion　of　asphalt　components　on　the　surface　of　Al2O3.　The　results　show　that　when　the　temperature　was　65　degrees　C,　asphalt　binder　showed　more　viscosity,　the　diffusion　speed　of　asphalt　components　ranked　according　to　their　molecular　mass,　which　was　saturate　＞　aromatics　＞　resin　＞　asphaltene.　At　25　degrees　C　and　165　degrees　C,　the　resin　had　the　fastest　diffusion　speed,　which　was　nearly　twice　of　asphaltene.　The　interaction　between　asphalt　components　and　Al2O3　mineral　surface　can　make　the　diffusion　of　asphalt　components　independent　on　temperature.