Herein,　a　novel　highly　selective　thin-film　composite　(TFC)　forward　osmosis　(FO)　membrane　with　high　water　flux　(Jw)　and　low　reverse　salt　flux　(Js)　was　fabricated　with　a　rationally　designed　sulfonated　covalent　organic　frameworks　(COFs)　as　an　interlayer.　This　membrane　was　designed　to　be　negatively　charged,　hydrophilic　and　has　the　synergistic　effect　of　the　selective　rejection　ability　of　the　COFs.　The　sulfonation　of　the　COFs　enhanced　its　hydrophilicity,　offered　negative　charges　and　narrowed　its　pore　size,　benefiting　the　salt　rejection.　Hydrolyzed　nylon　membrane　support　with　freed　surface　amino　groups　was　firstly　reacted　with　trimesoyl　chloride　(TMC)　to　become　hydrophilic　and　negatively　charged.　The　sulfonated　COFs　was　then　firmly　mounted　on　the　modified　support　via　H-bonding.　A　PA　layer　was　finally　formed　on　the　support　via　interfacial　polymerization.　The　prepared　TFC-FO　membrane　overcame　the　trade-off　between　Jw　and　Js　with　an　enhanced　FO　permeation　and　superior　selectivity　(Jw/Js　=　24.7　L/g)　in　FO　mode.　Both　the　sulfonated　COF　interlayer　and　TMC　modification　of　nylon　support　were　tested　to　be　crucial　to　the　high　performance.　The　new　strategy　reported　here　paves　a　way　for　taking　the　advantages　of　COFs　for　preparing　high-performance　FO　membranes.　©　2021