An elastomeric polyurethane/clay (PU/clay) nanocomposite based on poly(propylene glycol) (PPG), glycerol propoxylate, and toluene-diisocyanate (TDI) was synthesized by intercalative polymerization technology. The results of wide angle X-ray diffraction (WAXD) studies showed that the gallery distance of the clay in the hybrid was enlarged from 1.9 to 4.5nm or more. Introducing clay in the PU matrix resulted in an increase in both the tensile strength and elongation at beak. When the clay content reached about 8%, the tensile strength and elongation at break were two times and five times respectively to that of the pure PU. In addition, the clay intercalative route to the nanocomposite synthesis also effected the thermal properties of the nanocomposites.