Clear blends of chitosan with poly(N-vinyl-2-pyrrolidone) (PVP) made from aqueous solutions appear to be miscible from visual appearance. infrared (IR) spectra used to investigate the carbonyl-hydroxyl hydrogen bonding in the blends indicated compatibility; of two polymers on a molecular level. The IR spectra were also used to determine the interaction change accessing with increasing temperature and indicated that a significant conformational change occurred. On the other hand, the blend membranes were evaluated for separation of methanol from methyl tert-butyl ether. The influences of the membrane and the feed compositions were investigated. Methanol preferentially permeates through all the tested membranes, and the partial flux of methanol significantly increase with. the poly(N-vinyl-2-pyrrolidone) content increasing. The temperature dependence of pervaporation performance indicated that a significant conformational change occurred with increasing temperature. Combined with the IR results, the pervaporation properties are in agreement with characteristics of interaction between chain- chain within the blend membranes.