Abstract: This artiele presents the preParation of porous polysulfone menbrane from polysulfone,dimethylformamide and ethylene glyeol monomethyl ether with pore size of 200-300A.The main Parameters,sueh as eomposi-t ionof easting solution and eoagulation bath mixture,temperature of卜eoagulationbath,ambient humidity and state of easting solution,whieh affeet the membrane perfarmanee,are diseussed.Based on seanning electren m ierograph observation of the membrane strueture,reeommendation 15 made of the optimum presription and easting eonditions.