Abstract In this study, castor oil was modified to prepare hydroxyethyl methyl acrylate (HEMA) capped waterborne polyurethane-acrylate (UV-PUA) via in-situ and anionic self-emulsifying method. Ultraviolet (UV) curable UV-PUA film was obtained with IRGACURE 819 as photoinitiator. The properties of UV-PUA dispersions, such as appearance, viscosity and average particle size were investigated. The structure and thermal stability of UV-PUA film were characterized by Roman spectroscopy and DTG. Some mechanical properties of UV-PUA films, such as hardness, adhesion ability and water absorption property were measured. It was found that the viscosity of UV-PUA dispersion decreased while the average particle size increased with the increasing of n(NCO)/n(OH) value. The decomposition temperature of the UV-PUA film shifted to higher temperature as increasing of NCO/OH molar ratio. The C=C bond absorption peak at 1640cm−1 for UV-PUA film disappeared after UV radiation.