Transnational　power　cooperation　contributes　to　promoting　the　large-scale　use　of　renewable　energies　in　Asia,　but　how　to　develop　the　structure　of　power　transmission　network　deserves　careful　investigation.　This　paper　thoroughly　investigates　the　structure　of　power　investment　and　transmission　network　in　China　and　neighbouring　countries,　aiming　to　promote　the　large-scale　use　of　renewable　energies　around　Asia.　Various　power-generation　and　power-transmission　technologies　are　considered　in　detail,　and　transnational　power　interconnection　risk　cost　and　carbon　emission　cost　are　embedded　into　a　bottom-up　optimization　model.　The　future　power-generation　structures　and　networks　installed　under　various　policy　scenarios　are　analysed　in　detail,　and　the　corresponding　economic,　carbon　emission　reduction　and　renewable　energy　consumption　benefits　are　evaluated.　The　results　show　that　power　transmission　between　China＇s　internal　regions　and　neighbouring　countries　can　save　$56.7　billion　for　the　entire　power　system　through　the　large-scale　grid　integration　of　renewable　energy.　The　installed　capacities　of　wind　power,　solar　power,　and　hydropower　renewable　energy　power　generation　could　be　increased　by　141　GW,　163　GW,　and　58　GW,　respectively.　The　construction　of　transnational　transmission　lines　from　Central　Asia　to　Northwest　China,　Mongolia　to　North　China,　the　Russian　Far　East　to　Northeast　China,　and　Northeast　China　to　South　Korea　could　effectively　promote　the　utilization　of　renewable　energy　in　the　Russian　Far　East,　Mongolia　and　Central　Asia　and　further　reduce　carbon　emissions　in　China,　Japan　and　South　Korea.　©　2023