Aging　of　asphalt　binder　is　a　complex　natural　phenomenon　with　significant　differences　under　the　effect　of　different　environmental　factors.　The　accelerated　aging　method　commonly　used　in　the　laboratory　is　difficult　to　reproduce　the　field　aging　of　asphalt　binder.　The　purpose　of　this　study　is　to　reveal　the　effect　of　environmental　factors　on　the　aging　gradient　of　asphalt　binder.　For　this　reason,　a　layered　dissolution-peeling　method　was　developed　to　recycle　asphalt　binder　films.　The　gradient　behaviour　of　field-aged　asphalt　binder　was　analysed　based　on　rheological　parameters　and　chemical　functional　groups.　The　results　showed　that　the　layered　dissolution-peeling　method　achieved　separation　of　asphalt　binder　at　0.1　mm　level.　Ultraviolet　light　severely　contributed　to　the　distinct　aging　gradient　of　field-aged　asphalt　binder.　The　carbonyl　index　of　field-aged　asphalt　binder　at　0-0.32　mm　was　approximately　1.73　times　higher　than　that　at　0.32-0.64　mm,　1.90　times　higher　than　that　at　0.64-0.96　mm　and　2.24　times　higher　than　that　at　0.96-1.28　mm.　To　significantly　characterise　the　aging　behaviour　of　asphalt　binder,　the　film　thickness　in　the　accelerated　aging　simulation　test　should　not　be　more　than　1　mm.　The　findings　of　the　study　serve　as　a　valuable　reference　for　accurate　prediction　and　targeted　prevention　for　asphalt　pavements.