Epigallocatechin gallate (EGCG), green tea's main polyphenol, offers antioxidant and anti-aging benefits, but its application is limited by poor stability and low bioavailability. This study aimed to develop a novel, mild method for preparing ovalbumin (OVA) fibrils as a carrier to construct EGCG-OVA nanospheres, intending to enhance EGCG's stability and bioactivity while reducing OVA's allergenicity. OVA fibrils were prepared via a novel enzymatic hydrolysis and 50°C incubation method, yielding shorter, less rigid fibrils than traditional approaches. EGCG-OVA nanospheres were formed by co-incubating EGCG with these fibrils (7.5:1, w/w). Formation was driven by hydrophobic interactions, hydrogen bonds, and Schiff base condensation, the latter being critical for the fibril-to-sphere transition. The EGCG-OVA nanospheres' allergenic potential was evaluated in BALB/c mice. Results showed mitigated allergic symptoms compared to native OVA, achieved by modulating IL-4 and IFN-γ levels and restoring the Th1/Th2 immune balance. Furthermore, the anti-aging activity was assessed using aging mice and C. elegans . Compared to free EGCG, the nanospheres showed a more pronounced enhancement in antioxidant and anti-aging activities, which was linked to regulating the IGF1/Akt pathway. In conclusion, this study established a mild method for preparing OVA fibrils and successfully fabricated EGCG-OVA nanospheres. These nanospheres exhibited enhanced stability, potent bioactivity, and reduced allergenicity, offering a promising new strategy for EGCG delivery.