<p>Poly(vinyl alcohol) (PVA) hydrogels have garnered significant attention for tissue engineering, wound dressing, and electronic skin sensing applications. However, their poor mechanical performance severely restricts their multifunctional application in many scenarios. To address this limitation, PVA/tannic acid (TA)@carbon nanotubes (PVA/TA@CNTs) composite hydrogels with triple crosslinking networks were prepared through freezing-thawing and the solvent-induced shrinkage method, utilizing tannic acid-carbon nanotubes (TA@CNTs) as reinforcing units and a Ca²⁺ crosslinking strategy. The enhanced interfacial networks consisting of PVA crystalline domains, hydrogen bonding, and metal co-ordination endowed the composite hydrogel with a high mechanical strength, excellent flexibility, and fracture toughness, accompanied by a significant increase in crystallinity. The tensile strength and fracture toughness of the composite hydrogel reached up to about 7.0 MPa and 17.0 MJ/m³, which were roughly 8 and 10 times higher than neat PVA hydrogel, respectively. The composite hydrogel demonstrated good cytocompatibility, significantly addressing the challenge of balancing structural reinforcement with biosafety in hydrogels. This methodology establishes a rational design for fabricating mechanically robust yet tough PVA hydrogels for biomedical applications.</p>