The　use　of　antioxidants　in　asphalt　binder　is　significant　in　prolonging　the　service　life　of　asphalt　pavements.　In　order　to　improve　the　aging　resistance　of　asphalt　binder,　an　antioxidant　was　mixed　into　SBS　modified　asphalt　binder　in　this　study.　The　effects　of　the　antioxidant　on　the　properties　and　aging　resistance　of　SBS　modified　asphalt　binder　were　characterised　based　on　rheological　parameters,　chemical　composition　and　morphology.　The　results　showed　that　the　aging　resistance　index　quantitatively　evaluated　the　aging　resistance　of　different　asphalt　binders.　The　average　aging　resistance　index　of　asphalt　binder　with　3%　antioxidant　based　on　different　properties　index　was　about　3.5,　which　meant　it　can　prolong　the　aging　life　by　approximately　3.5　times.　The　control　of　carbonyl　and　sulfoxide　formation　by　antioxidant　was　the　key　driver　to　inhibit　the　macroscopic　property　degradation　of　asphalt　binder.　However,　the　antioxidant　did　not　effectively　inhibit　the　degradation　of　SBS　modifiers　during　aging.