Water-borne epoxy acrylate system using a urethane acrylate anionomer as a cotabilizer was prepared for an application of ultraviolet(UV) curing. By observing the optical microscopy and gravimetric stability. it was confirmed that the urethane acrylate anionomers incorporated have a drastic effect on costabilizing the interface of epoxy acrylate and water/ethanol mixture (80/20, w/w). This was possible by the structurally designed urethane acrylate anionomer, containing a hydrophobic soft segment and two hydrophilic ionic segments in a molecule. In addition, when cured, the epoxy acrylate film displayed the improved toughening properties, because of the formation of rubber domains of the urethane acrylate anionomers caused by the difference of solubility between the urethane acrylate and epoxy acrylate matrix.