Thermoplastic UV-curable PU was successfully synthesized by using methylene diphenyl diisocyanate (MDI), poly(tetramethylene ether) glycol, and the tri-acrylate derivatives as a crosslinking point. The short exposure to 200~400nm UV radiation formed the crosslinked PUacrylate elastomers. The structures and properties of the resulting Acryl-PUs were evaluated by Fourier transform infrared spectroscopy (FT-IR), ultra violet spectroscopy (UV-Vis), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and universal testing machine (UTM). The different molecular weight of the PU-acrylate elastomers led to higher tensile strength and hardness due to the increased crosslinking density and the enhanced interchain hydrogen bonding.