［Objective］ To address the problem that waterborne epoxy resins used in metalanticorrosive primers tend to form brittle coatings with poor toughness and a propensity for cracking.These cracks allowed corrosive media to penetrate through coating defects and corrode the underlyingmetal substrate.［Methods］ Four dicarboxylic acids were synthesized from 2-butyl-2-ethyl-1，3-propanediol and acid anhydrides. These dicarboxylic acids were then reacted with epoxy resin E-51and the resulting products were subsequently converted into waterborne systems to obtain four modifiedwaterborne epoxy resins. The structures of both the dicarboxylic acids and the modified epoxy resins werecharacterized by proton nuclear magnetic resonance（1HNMR）spectroscopy and infrared spectroscopy.The mechanical properties of the cured films from the modified epoxy resin varnishes were investigatedby dynamic thermomechanical analysis. In addition，the application performance of epoxy anticorrosive coatings using the modified epoxy resins as film-forming binders was evaluated.［Results］ The waterborne epoxy cured film and corresponding coating prepared from methyl hexahydrophthalicanhydride exhibited the best overall mechanical and anticorrosive properties. The tensile strength of thecured film reached 32. 1 MPa，with an elongation at break of 79. 3%. The coating's salt spray resistance reached 384 h，its water resistance at 40 ℃ reached 480 h，and its acid resistance reached 168 h.［Conclusion］ Dicarboxylic-acid-modified waterborne epoxy resins could effectively improve the toughness and durability of coatings，demonstrating promising potential for practical applications.