With the development of the new energy industry in high-altitude regions, epoxy resin insulating materials in electrical equipment face severe challenges from prolonged exposure to strong radiation environments. Strong ultraviolet irradiation induces the generation of free radicals such as alkyl (CH₂), alkoxy (CH₂O), and peroxyl (CH₂OO), which continuously attack the cross-linking structure of epoxy resin, leading to its degradation. This study employs molecular dynamics simulations to evaluate the enhancing effect of graphene quantum dots (GQDs) on the radiation resistance of epoxy resin (EP), proposing cross-linking structural integrity as an evaluation criterion. It compares and analyses pure EP (EP/neat), hydrogen-terminated GQDs (EP/GQD_C₅₄H₁₈), and carboxyl-terminated GQDs (EP/GQD_COOH) under three types of free radicals. The results indicate that the unique sp² hybrid structure and hydrogen-donating ability of GQDs can effectively inhibit the activity of free radicals, and improve the integrity of the cross-linked structure by 8% to 16% compared to EP/neat. While both types of GQDs demonstrate comparable behavior in response to alkyl free radicals, EP/GQD_COOH exhibits superior performance under the influence of oxygen-containing free radicals. This enhanced performance can be attributed to its augmented hydrogen-donating capacity and an increased number of active sites. This study investigates the extent to which GQDs with different structures enhance the radiation resistance of epoxy resins, providing an important theoretical basis for the modification of epoxy resins for applications in high-radiation environments.