Addressing　the　current　surge　in　blockchain　applications　and　the　increasingly　significant　throughput　and　scalability　challenges　of　single-chain　systems,　we　propose　a　cross-chain　protocol　based　on　a　main-subchain　architecture,　utilizing　a　＇　1+N＇　model　composed　of　a　main　blockchain　and　multiple　sidechains.　The　main　blockchain　is　a　permissioned　public　blockchain　that　employs　relay　chain　technology,　combining　the　flexibility　and　scalability　of　public　blockchains　with　the　performance,　security,　and　regulatory　advantages　of　federated　blockchains.　It　serves　as　the　core　of　the　architecture,　managing　and　coordinating　the　operations　of　the　sidechains.　Sidechains　maintain　a　high　degree　of　independence,　selecting　consensus　algorithms　tailored　to　their　specific　business　needs　and　processing　transactions　asynchronously　across　different　chains.　Cross-chain　transactions　are　decomposed　into　multiple　sub-transactions,　which　are　independently　processed　and　verified　by　the　relevant　sidechains　and　the　committee　blockchain.　This　architecture　ensures　the　atomicity,　consistency,　and　security　of　transactions　while　enhancing　the　system＇s　parallel　processing　capability　and　overall　performance.　Finally,　this　paper　demonstrates　the　superiority　of　the　proposed　scheme　in　terms　of　fund　security,　atomicity,　consistency,　continuity,　and　dynamics　through　theoretical　analysis.　©　2024　IEEE.