In　asphalt　mixture,　aggregates　account　for　up　to　90%　of　the　total　volume　and　play　an　important　role　in　the　mechanical　characteristics　of　asphalt　mixture.　The　proportions　of　fine　and　coarse　aggregates　in　gradation,　as　well　as　the　function　of　aggregate　particles,　are　important　factors　for　the　skeleton　structure　performance　of　asphalt　mixtures.　However,　the　existing　asphalt　mixture　design　methods　are　mostly　based　on　empirical　methods,　where　the　non-uniformity　and　complexity　of　the　composition　of　asphalt　mixtures　are　not　fully　studied.　In　this　study,　the　skeleton　structure　of　aggregate　mixture　and　function　of　aggregate　are　studied　and　analyzed　using　the　Discrete　Element　Method　(DEM).　The　Particle　Flow　3D　(PFC3D)　DEM　program　is　used　to　perform　the　numerical　simulation.　The　average　contact　number　and　interaction　forces　by　aggregate　particles　of　different　sizes　are　obtained　and　studied.　The　skeleton　structure　of　aggregate　mixture　and　function　of　aggregate　particles　are　further　analyzed　from　the　meso-structural　perspective.