Epoxy　resins　are　commonly　utilized　for　their　robust　strength　and　high　modulus.　However,　their　brittleness　is　a　drawback　caused　by　their　elevated　cross-linking　density,　which　restricts　their　suitability　for　numerous　applications.　In　this　study,　natural　eucommia　ulmoides　gum　(EUG)　underwent　modification　with　maleic　anhydride　(MA)　and　was　used　to　toughen　epoxy　resin.　The　modified　EUG　contains　active　sites　that　effectively　participate　in　the　curing　process　of　epoxy　resin,　resulting　in　lower　cross-linking　density.　Additionally,　during　the　curing　process,　EM　particles　cluster　together　and　form　a　＇sea-island＇　structure,　providing　epoxy　resin　with　an　additional　mechanism　for　energy　dissipation　and　enhancing　its　damage　resistance.　The　incorporation　of　1%　EM　results　in　a　26.5%　increase　in　the　fracture　toughness　and　a　40%　increase　in　the　elongation　at　break　of　epoxy　resin.　This　research　offers　a　validated　approach　for　utilizing　biobased　materials　to　reinforce　the　toughness　of　epoxy　resin.　©　2024　American　Chemical　Society.