In this study, a macroinitiator of beta-CD-ONa was prepared by a substitution reaction of beta-cyclodextrin (beta-CD) with sodium (Na). The macroinitiator was then used in the ring-opening polymerization of octamethylcyclotetrasiloxane (D-4) to obtain a star polymer, in which beta-CD is the core and polysiloxane is the arm. FTIR, NMR, TGA, CA, etc., were used to characterize the structure and properties of star polymers. The results indicated that there were four polysiloxane arms attached to each beta-CD core, and the star polymer had good thermal stability. With the increase in D(4)monomer dosage, the hydrophobicity of the star polymer slightly improved, but the reaction time had no significant effect on hydrophobicity. When the star polymer was coated onto polyethylene terephthalate membrane, the transmittance increased from 87.6% to 92.8%, and the haze did not change significantly. Furthermore, the surface of star polymer porous membranes was prepared by the static breath-figure method usingn-hexane as solvent at 30 degrees C. The results showed uniform pore distribution and increased hydrophobicity.