Abstract: Waterborne polyurethane (PU) aqueous dispersions were prepared by the modification with butyl acrylate (BA) and 2-hydroxyethyl methacrylate (HEMA)，in which the PU was synthesized from isophorone diisocyanate (IPDI) with dihydroxymethylpropionic acid (DMPA) as the hard segment and polyether polyols (N220) as the soft segment. The physical and mechanical properties of the prepared aqueous dispersions and membranes were investigated. Results showed that the modified PU has a larger particle size，a smaller surface tension and improved mechanical properties and hardness as compared with the unmodified PU. The introduction of HEMA resulted in the formation of a chemical crosslinked core–shell interpenetrating polymer network structure，indicating that the hard segment of PU has a higher molecular chain compatibility with the acrylic polymers in the modified materials.