Abstract: The preparation of porous membrane by supercritical CO2 fluid is a new method with many advantages. In this paper，the principle of preparation is introduced，and the influences of such conditions as pressure，concentration of polymer，temperature are analyzed. The final structure of porous membrane is decided by the diffusion speed of supercritical CO2 fluid inside the polymer and the plasticizing effect of polymer caused by supercritical CO2 fluid. In addition，the unique advantage sof the method is summarized.

摘要： 介绍了超临界CO2流体用于微孔分离膜制备机理；分析了压力、聚合物浓度及温度等条件对膜孔结构的影响；论述了CO2对聚合物增塑作用的大小和CO2在聚合物材料中向外扩散的速率是最终影响膜孔结构形态的两个基本因素；综述了超临界CO2流体用于分离膜的制备的独特优势。