Bismaleimide resin (BMI) is a thermosetting resin with excellent properties. However, due to its poor toughness as a cured product, this paper uses hyperbranched polyimide (HBPI) and nano‐SiO2 in a synergistic manner to improve the performance of BMI. Isophorone diisocyanated tripolymer (IPDI trimer) and methyl nadic anhydride (MNA) were used to synthesize HBPI, and then we investigated the effect of the synergistic modification on the mechanical and thermal properties and the modification mechanism of HBPI and nano‐SiO2. The experiments showed that the most significant improvements were achieved at the addition of 40 and 3 wt% of HBPI and nano‐SiO2 respectively, with the impact strength of the materials increasing by 97.2%, fracture toughness indexes GIC and KIC increased by 36.7% and 34.6% respectively and glass transition temperature (Tg) was reduced. The SEM results showed that the nanoparticles were uniformly dispersed and further validated the synergistic modification mechanism.

No abstract