Abstract: The influence of dibutyl phthalate contents on mechanical properties and glass transition temperature of several copolyether polyurethanes and polyurethaneureas based on different relative molecular mass ethylene oxide-tetrahydrofuran copolyether, 1,4-diphenyle methane diisocyanate/isophorored diisocyanate, 1, 4-butanediol/ethylene diamine were studied. All prepared TPE exhibited satisfactory strength and extention ability. The miscibility between DBP DBP and elastomers were also estimated and determined .