PPO/PSF　composite　membrane　was　prepared　by　solvent　evaporation　method,　and　by　taking　polysulfone　ultrafiltration　membrane　as　the　basement　membrane.　The　preparation　effect　of　the　composite　membrane　was　investigated　by　FT-IR　and　its　section　morphology　was　observed　by　scanning　electron　microscopy　(SEM).　Effects　of　influence　of　casting　solution　composition,　feed　solution　concentration　and　feed　solution　temperature　on　separation　performance　of　composite　membrane　were　also　studied.　The　results　show　that　with　increasing　of　PPO　concentration　in　the　membrane　solution,　composite　membrane　separation　factor　increases　and　permeation　flux　decreases.　With　increasing　of　ethanol　concentration　in　the　feed　solution,　the　composite　membrane　separation　factor　decreases,　while　permeation　flux　also　increases.　With　increasing　of　feed　solution　temperature,　both　composite　membrane　separation　factor　and　permeation　flux　increase.　It　is　also　found　that　the　PPO/PSF　composite　membrane　exhibits　high　separation　performance.　The　total　permeation　flux　and　the　separation　factor　for　ethanol　can　be　157.2　g/(m2·h)　and　15.6　respectively,　when　PPO　concentration　in　casting　solution　is　14%,　the　feed　concentration　is　10%　and　the　feed　solution　temperature　is　60°C.