<p>Herein, a novel modified waterborne polyurethane acrylate (WPUA) emulsion is prepared using an itaconic acid (IA)-based epoxy acrylate. The structure of the IA-based epoxy acrylate is confirmed by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopy. In addition, the WPUA manufacturing process is analyzed in detail via FTIR tracking. The effects of various doses of the IA-based epoxy acrylate during the fabrication and coating of the film are investigated by tensile testing, dynamic mechanical analysis, and gravimetric analysis. The results show that the average particle size of the emulsion gradually decreases as the content of the IA-based epoxy acrylate increases, and the tensile strength of the cured film is improved by up to 19%. In addition, the gel fractions of all samples exceed 95%, indicating a high degree of crosslinking. While the TGA curves were largely superimposable, relatively improved resistance to thermal degradation was observed in specific decomposition regions. These enhancements contribute to the development of modified WPUA as a promising material for flexible coatings and sustainable applications.</p>