Asphalt　rejuvenation　technology　is　an　effective　method　to　recycle　reclaimed　asphalt　pavement　(RAP)　for　the　production　of　high-quality　recycled　asphalt　mixtures.　This　approach　contributes　to　mitigating　environmental　pollution　and　facilitating　resource　recycling.　In　this　study,　the　impact　of　rejuvenator　molecules　on　the　rejuvenation　process　was　explored　by　utilizing　theoretical　models　and　dynamics　simulations.　Free　volume　theory　models　were　used　to　calculate　the　diffusion　coefficient,　while　molecular　dynamics　(MD)　simulations　revealed　the　internal　energy　changes　during　diffusion.　Molecules　with　high　interaction　with　aged　asphalt　are　easier　to　reach　the　homogeneous　state　in　diffusion　systems　under　higher　temperatures.　The　quantification　of　blending　by　Fick＇s　2nd　law　suggests　that　the　blending　process　consists　of　three　stages:　an　intense　diffusion　phase,　a　stabilization　phase,　and　a　homogeneous　state　phase.　The　time　taken　to　reach　the　homogeneous　stage　depends　on　the　chemical　structure　of　the　rejuvenators　and　the　temperature.　This　study　elucidates　the　molecular-scale　mechanism　of　RAP　rejuvenation　and　provides　a　roadmap　for　improving　environmentally　friendly　RAP　rejuvenation　technology.　©　2023　Elsevier　Ltd