Interesting properties of polyurethane (PU) elastomers are based on the component materials. Polyrotaxane (PRX) is a macromolecule in which plural ring molecules are interlocked by a linear polymer chain with bulky terminal cap. One of the unique properties of PRX is free sliding of the ring molecules along the linear chain. Hence, hybridization of PRX and PU structures makes it possible to fabricate a novel PU elastomer possessing both the properties. In this presentation, we describe the synthesis of PU-PRX hybrids and their thermal and elastic properties. The PU-PRXs were synthesized with MDI, PTMG2000, and PRXs, which consist of partially methylated α-cyclodextrin (CyD) and PEG4000(or PEG6000), using a prepolymer method. Here, the PU-PRXs are abbreviated as PURa(b)c, in which a, b, and c indicate the PEG length, filling ratio of CyD in PRXs, and NCO index, respectively. In this work, we prepared 6 PURs: PUR4000(63)1.5, PUR4000(60)1.0, PUR4000(43)1.5, PUR6000(59)1.0, PUR6000(50)1.5 and PUR6000(37)1.5. All the PURs left their gel components in DMSO, indicating the existence of the intermolecular crosslinks between the PRXs. The Tgs of PURs with the NCO index of 1.0 increased because the number of PTMG chain grafted from PRX decreased. The Tc and Tm of the PTMG segment were distinctly observed together with a decrease in the filling ratio. In addition, the tan δ values of PURs with higher filling ratios did not decrease after Tg. From the thermal properties, we expect that the higher filling of CyD would provide the structure where loosely filled CyD part and tightly filled one exist in the PRX unit, and interconversion between the loosely filled CyDs and tightly filled CyDs could be possible after Tg. PUR4000(60)1.0 showed the best elongation of 1458%. As a trend, PUR4000s gave better elongation compared to PUR6000s. The elongation behavior seems to be affected by the ratio of the lengths of PRX and PTMG rather than the filling ratio.