The relationship between the structure and property of polyurethane elastomer derived from bisphenol-S derivatives/diisocyanate system was studied. The effects of the amount of soft segment of diol, including ester and ether, as well as the effects of structure of diisocyanate on the mechanical properties of elastomer were discussed on the basis of the results obtained from the hardness, tensile strength, elongation, swelling, dynamic mechanical analysis, and X-ray diffraction. Also, the thermal properties of polyurethane elastomer were also investigated by d.s.c. and t.g.a. analyses. The d.s.c. and dynamic properties results demonstrated that the new polyurethanes exhibit a range of glass transition temperatures from -25 to 48 degrees C, and temperature at loss tan delta peak from 81.0 to 13.7 degrees C. Moreover, t.g.a. results showed that the addition of an ester group increased the thermal stability of polyurethanes.