A　facile　approach　to　fabricate　fluorinated　molecular　monolayer　on　the　surface　of　polydimethylsiloxane　(PDMS)　membrane　was　conducted　using　fluoroalkylsilane　(FAS)　as　cross-linking　agent.　In　detail,　hydroxyl　terminated　PDMS　were　cross-linked　with　1H,　1H,　2H,　2H-Perfluorodecyltriethoxysilane　and　cast　on　porous　polysulfone　support　to　prepare　PDMS　membranes.　X-ray　photoelectron　spectroscopy　showed　that　fluorinated　alkyl　chains　were　enriched　at　the　surface　of　the　membranes.　Moreover,　the　surface　fluorine　concentration　increased　with　the　increasing　of　FAS　and　plateaued　at　around　55　at%　(close　to　that　of　FAS　molecules)　when　the　surface　was　fully　covered　by　fluorinated　monolayers.　The　surface　hydrophobicity　was　proportional　to　the　surface　fluorine　content　as　revealed　by　water　contact　angle　measurement.　When　applied　in　pervaporation　separation　of　1　wt%　n-butanol/water　mixture　at　60　degrees　C,　the　membrane　prepared　with　a　FAS　ethoxy　to　PDMS　hydroxyl　equivalents　ratio　of　35　(PDMS-FAS-35)　exhibited　a　flux　of　843　g(-2)　h(-1)　and　an　enhanced　permeate　n-butanol　concentration　of　34.3　wt%　compared　with　PDMS　cross-linked　with　traditional　TEOS　(1375　g(-2)　h(-1),　24.4　wt%).　The　decrease　of　permeate　flux　was　because　of　the　reduced　water　partial　flux　without　sacrificing　the　butanol　partial　flux　on　the　consequence　of　water　repellency　of　FAS　monolayer.　The　results　indicated　that　the　FAS　cross-linked　PDMS　could　increase　the　separation　efficiency　of　the　membrane,　thereby　reducing　the　cost　and　energy　consumption　of　the　pervaporation　process.