Abstract: 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 ℃.