Dynamic covalent epoxy resins integrate the merits of thermoplastics and thermosets, enabling reprocessability while maintaining covalent crosslinking. However, achieving simultaneous shape memory, intrinsic flame retardancy, and antibacterial properties in biomass-derived epoxy resins remains a significant challenge. Inspired by mussel byssus, we developed a supramolecular strategy to construct cardanol-based epoxy resins incorporating adaptive phosphate networks and robust dynamic noncovalent interactions. The synergistic effects of supramolecular interactions and entropy-driven dynamics enabled by functional group engineering endowed the material with shape memory (Rf = 99%, Rr = 80%), self-healing, and reprocessability. The conjugated π-bond system of benzene rings, phenolic hydroxyl radical scavenging, and dynamic phosphate ester carbonization collectively enhanced flame retardancy. The resins achieved a limiting oxygen index of 30.3% and V0 rating under UL-94 standards. Furthermore, the synergistic antibacterial activity of phenolic polyphenols and phosphate esters resulted in 100% antibacterial efficiency against Staphylococcus aureus. This mussel-inspired supramolecular design establishes a sustainable platform for next-generation epoxy resins, offering multifunctional performance critical for medical and food packaging applications under stringent flame retardancy and antibacterial requirements.