The　massive　discharge　of　oily　wastewater　and　the　frequent　occurrence　of　oil　spills　have　posed　serious　threat　to　human.　Hence,　it　is　important　to　develop　functional　materials　and　related　methods　to　achieve　efficient　oil/water　separation.　Herein,　a　new　superhydrophobic　COF　(named　SCOF)　was　designed　and　successfully　synthesized　with　functional　alkoxy　side　chains　at　room　temperature　for　the　first　time　and　was　then　applied　to　oil/water　separation.　By　loading　SCOF　onto　the　fabric,　the　prepared　superhydrophobic　Fabric@SCOF　membrane　could　effectively　separate　different　oil/water　mixtures,　and　the　separation　efficiency　was　higher　than　99　%.　Noteworthy,　when　separating　immiscible　CH2Cl2/water　mixture,　the　maximum　oil　flux　was　63,129　L　m−2　h−1　and　the　separation　efficiency　reached　99.8　%.　To　the　best　of　our　knowledge,　this　was　the　highest　oil　flux　of　superhydrophobic　COF-based　membrane　prepared　on　the　fabric　substrate　for　the　separation　of　immiscible　oil/water　mixture　only　in　gravity.　By　loading　SCOF　onto　porous　melamine　sponge,　the　fabricated　Sponge@SCOF　could　adsorb　different　oils,　and　the　adsorption　capacity　for　CCl4　could　reach　151　g/g.　This　work　provides　insights　for　the　design　and　synthesis　of　novel　functional　COFs,　and　broadens　the　application　of　COF-based　superhydrophobic　composite　in　oil/water　separation,　which　is　of　great　significance　for　oily　wastewater　treatment　and　environmental　remediation.　©　2025　Elsevier　Inc.