Bio-inspired molecular design and synthesis of high-performance and recyclable cross-linked polymers is reported. Reversible cross-links between hard segments are incorporated into linear segmented polyurethane via Diels-Alder reaction between maleimide pendant group and furan cross-linker. The materials form hierarchical structure and exhibit excellent properties with high stiffness, strength and toughness, and can be easily thermally reshaped and re-mended.