Abstract: Waterborne polyurethane adhesive emulsions were synthesized with isophorone diisocyanate（IPDI），dihydromethyl propionic acid（DMPA），polyester glycol（XH-111），trimethylolpropane（TMP）and 1,4-butanediol（BDO），and then reacted with hydroxy-ethyl acrylate（HEA）to cap the —NCO terminal groups. Such polyurethane emulsions were used to further copolymerize with acrylates to synthesize modified waterborne polyurethane composite emulsions through free-radical polymerization. Structure and thermal stability of the modified and unmodified polyurethanes were studied by FTIR and TGA，and effects of —COOH content，polyacrylate content and mass ratio of MA to BA on water resistance，mechanical property and bonding strength of the obtained polyurethane adhesive were discussed. Results showed that the water resistance，thermal stability and flexibitity of modified polyurethane adhesive behaved outstanding performance with bonding strength of 5.9 N/mm，in which —COOH content was 1.48% to 1.50%，polyacrylate content was 30% and the mass ratio of MA to BA was 4∶2.