For dehydrating separation aqueous alcohol solution by the pervaporation technique, a chemical modified poly(4-methyl-1-pentene) (TPX) membrane was synthesized with 4-vinylpyridine (4-VP). The morphology, crystallinity, and thermodegradation properties were investigated by scanning electron microscopy, X-ray, and thermogravimetric analysis, respectively. The modified TPX membrane possessed higher stability than that of the unmodified TPX membrane. The effects of feed temperature and poly(4-VP) (P4-VP) content of the modified TPX membranes on the performances of pervaporation were studied. A separation factor of 133 and a permeation rate of 115 g/m(2)h can be obtained for the TPX/P4-VP membrane with 3.0 wt % P4-VP content.