Abstract: In this paper,the synthesis of interpenetrating polymer networks(IPN) based on polyurethane (hydroxy terminated eopolymer of butadiene-acrylonitrile crossliked with 2, 4-tolylene diisocyanate) and polyepoxide (crossliked with DMP-30)by simultaneous method and the influence of various factors on their morphology and glass transition behavior were reported. The curing condition of testing specimen was selected with the aid of JSRtype curelastometer . The morphology and glass transition of the tested material were studied by transmission electron microscopy (TEM) and dynamic mechanical spectroscopy (DMS) techniques respectively and the thermostability and mechanical behavior of the sample were investigated as well. The results show that PU/PEbelongs to inconsistent system. In all the cases, a two-phase morphology emerged and the celluar structure with the cell sizes ranging from 400 Å to 800 Å was found. The damping value is increased and the zone of T_g transition is broadened by adjusting the constituent ratio and adding various chain extender.