G　protein-coupled　receptors　(GPCRs),　a　large　superfamily　of　transmembrane　(TM)　proteins,　allosterically　transduce　the　signal　of　ligand　binding　in　the　extracellular　(EC)　domain　to　couple　to　effector　proteins　in　the　intracellular　(IC)　domain,　therefore　forming　the　largest　class　of　drug　targets.　The　A(2A)adenosine　receptor　(A(2A)AR),　a　class-A　GPCR,　has　been　extensively　studied　as　it　offers　numerous　possibilities　for　therapeutic　applications.　However,　the　mechanism　of　allosteric　communication　between　EC　and　IC　domains　is　not　completely　clear.　In　this　work,　we　utilize　torsional　mutual　information　to　quantify　the　correlated　motions　of　residue　pairs　from　its　molecular　dynamics　(MD)　simulation　trajectories,　and　further　use　the　complex　network　model　to　obtain　allosteric　pipelines　and　hubs.　The　identified　allosteric　communication　pipelines　mainly　transmit　the　signal　from　EC　domain　to　the　cytoplasmic　ends　of　TM　helix　5　(TM5),　TM6　and　TM7.　The　allosteric　hubs,　mostly　located　at　TM5,　TM6　and　TM7,　play　an　important　role　in　mediating　allosteric　signal　transmission　to　keep　the　receptor　rigid　and　prevent　G　protein　from　binding　to　IC　domain,　which　can　explain　the　reason　why　their　mutations　distant　from　ligand-binding　site　do　not　affect　the　ligand　binding　affinity　but　affect　the　ligand　efficacy.　Additionally,　we　identify　the　key　residues　located　in　antagonist　ZM241385　binding　pocket　which　mediate　multiple　allosteric　pathways　and　have　been　experimentally　proven　to　play　a　critical　role　in　affecting　the　ligand　potency.　This　study　is　helpful　for　understanding　the　allosteric　communication　mechanism　of　A(2A)AR,　and　can　provide　valuable　information　for　the　structure-based　drug　design　of　GPCRs.　Communicated　by　Ramaswamy　H.　Sarma