Cellulose acetate hollow fiber membrane were prepared by melt spinning. Several kinds of cellulose acetate (CA) and polyethylene glycol (PEG) were used. The resulant fibers were of optimum size, i.e., 200㎛ of I.D., and 40㎛ of wall thickness, which are the same sizes as C-DAK 3500 of Cordis Dow Co.. As the ratio of PEG to CA and molecular weight of PEG incereased, solute permeability and ultrafiltration rate also incereased. When CA-398-30 cellulose acetate and PEG (#600) were mixed at 100 to 100 ratio, urea permeability was 2.69×10^-2cm/min and ultrafiltration rate was 3.40ml/hr.m². mmHg. Among the post-treatment steps, the first extraction of PEG in hot water bath had significant effects on the membrane performances and the degree of stretching was closely related to mechanical strength of hollow fiber and the membrane performances. The stepwise change of morphology of cross-section of hollow fiber was observed with the scanning electron microscope.