Abstract: In this study,mesoporous molecular sieves were first modified by silazanes,and then doped into polydimethylsiloxane(PDMS) solution. The mixture was coated on polysulfone membrane to obtain organic-inorganic hybrid composite membrane. The modified mesoporous molecular sieves were characterized by BET and FT-IR. The results of BET showed that pore size distribution of mesoporous molecular sieves significantly changed before and after modification. It could be observed from FT-IR that hydroxyl peaks of the mesoporous molecular sieve decreased and even disappeared after being modified.Simultaneously,the alkyl characteristic peaks appeared. The surface and cross-section morphologies of the hybrid composite membrane were characterized by SEM. The effects of molecular sieves content,feed concentration and operation temperature on the pervaporation performance were systematically investigated.Resultsindicated that the hydrophobic of mesoporous molecular sieves modified by 1,1,3,3-Tetramethyldisilazane obviously increased. The modified mesoporous molecular sieves/PDMS hybrid composite membrane had an excellent performance in the separation of alcohol/water solution. When the doping amount of molecular sieve was 20%,the feed concentration was 3%,separation factor of thehybrid membrane for ethanol/water mixture was 9. 8 with the permeation flux of 1 002 g/(m²·h),and separation factor of the n-butanol/water mixture could reach 65. 4 with the flux of 1 402 g/(m²·h) at 40℃.