Bioethanol　has　achieved　increasing　attention　in　alleviating　energy　crisis　and　environmental　issues.　Pervaporation　could　be　a　promising　technology　to　separate　ethanol　from　fermentation.　Traditionally,　the　liquid　polymetric　solution　was　compounded　on　solid　porous　supports　to　form　composite　membranes.　Through　this　liquid-solid　interface,　it　is　challenging　to　precisely　control　the　structure　and　achieve　high　pervaporation　performance.　In　this　work,　we　aimed　to　overcome　some　of　these　limitations　and　designed　a　polyether　block　amide　(PEBA)　per-vaporation　membrane　by　dropping　the　membrane　solution　on　a　water　surface.　While　the　membrane　solution　spreading,　solvent-water　exchange　and　solvent　evaporation　occurred.　Thereafter　the　polymer　precipitation　was　induced　in　the　solvent-water　interface.　The　defect-free　and　uniform　selective　layer　with　a　thickness　of　3.9　mu　m　was　achieved　by　optimizing　the　ratio　of　solvent,　and　the　temperature　of　the　water.　The　PEBA　layer　was　deposited　onto　porous　polytetrafluoroethylene　(PTFE)　substrate　for　recovering　ethanol　from　water　by　pervaporation.　The　membrane　represented　a　total　flux　and　separation　factor　of　3.9　kg　m-　2　h-1　and　4.9,　which　was　maintained　stable　for　100　h.　The　interface-induced　membrane　demonstrated　high　separation　performance　and　membrane　stability.