Abstract: The continuous improvement of the integration of electrical and electronic equipment has put forward higher demands on the comprehensive thermodynamic performance of epoxy composites. "Seesaw" phenomenon exists between heat resistance, rigidity and toughness of epoxy composites, and it is difficult to improve synergistically. In this study, the three curing agents of hexahydrophthalic anhydride/ tetrahydrophthalic anhydride/phthalic anhydride are compounded to improve the thermalperformance of epoxy composites. And 2—toluene glycidyl ether is used to synergistically improve the toughness and rigidity of epoxy composites. The study shows that the method of curing agent compounding increases the T_g and T_5% of epoxy composites by 17.93% and 7.72%, respectively; the 2—tolyl glycidyl ether modification results in the 123.03% and 61.71% increase in impact strength and flexural strength of the epoxy composites, respectively. Molecular dynamics simulations are used to reveal the mechanism of 2—toluene glycidyl ether from a molecular perspective. Its rigid benzene ring group enhances the stability of the molecular structure of the epoxy system, and the flexible —C—O—C— chain segment improves the flexibility of the cross-linked system. A possible method to enhance the toughness and rigidity of epoxy composites without degrading their thermal performance is proposed in this study, which provides a new idea for the design of epoxy composites formulations with high integrated thermomechanical performance.