For an environmentally-friendly coating, waterborne UV-curable poly-urethane acrylates were synthesized with different mixing ratios of 4,4-methylene dicyclohexyl diisocyanate (H12MDI) and isocyanate-functionalized aliphatic acrylic ester (IAAE). Physical properties of the synthesized polyurethane acrylates were measured as a function of mixing ratio. Molecular structure and physical properties of the synthesized waterborne UV-curable polyurethane acrylate were investigated by FT-IR and analyzers on particle size, tensile strength, pencil hardness, and adhesion. The results showed the tensile strength and pencil hardness of the cured coatings increased with IAAE while their elongation decreased. These trends would be due to the high reactivity of IAAE which leads to high cross linking density. The optimum physical properties were obtained by controlling the mixing ratio.