Islands　occupy　an　important　strategic　position　in　the　development　of　a　country,　but　the　water　supply　system　of　islands　faces　the　hidden　problem　of　insufficient　water　supply,　and　reverse　osmosis　desalination　technology　plays　an　important　role　in　solving　this　problem.　However,　existing　studies　on　the　configuration　of　water-energy　nexus　systems　on　islands　have　oversimplified　the　description　of　the　desalination　model　and　have　not　considered　the　requirements　of　different　water　loads　for　the　concentration　of　solutes　in　the　but　also　water.　In　this　paper,　a　method　for　optimizing　the　configuration　of　water-energy　nexus　systems　on　sea　islands　considering　multistage　desalination　is　proposed.　Firstly,　a　comprehensive　mathematical　model　of　water-energy　nexus　system　integrating　wind　energy,　hydrogen　energy,　and　reverse　osmosis　desalination　is　established.　Secondly,　considering　the　coupled　equipment　characteristics　of　the　water　network　and　the　distribution　network,　the　water　network　and　the　distribution　network　flow　model　is　established.　Finally,　a　reasonable　configuration　is　obtained　by　solving　the　optimization　objective　of　the　lowest　integrated　cost　of　the　island　water-energy　nexus　system,　and　the　influence　of　the　reverse　osmosis　membrane　parameters　on　the　cost　of　the　whole　system　is　analyzed.　©　2024　IEEE.