As load-bearing material in biomedical-applications as cartilage replacement, artificial meniscus and tendons,etc., poly(vinyl alcohol) (PVA)/graphene oxide (GO)-tannic acid (TA) nano-composite hydrogelswith multiple-crosslinking network were fabricated by establishing freezing/thawing-annealing-swellingmethod. By TA anchoring, PVA molecules were grafted onto GO surface efficiently, and strong interfacialinteraction led to exfoliation and uniform distribution of GO in matrix. By introducing annealing process,the crystallinity and crystallite size of PVA increased and introducing GO-TA led to more perfect and densercrystalline structure, while physical crosslinking network centered on GO-TA and hydrogen bondabundantcrystalline phase formed, resulting in increasing crosslinking density of hydrogel. By furtherswelling in CaCl2 aqueous solution, hydroxyl-Ca2+ coordination formed, and multiple-crosslinking networkwas constructed with high crosslinking density. The tensile strength and fracture toughness of compositehydrogel were remarkably improved, reaching 14.38 MPa/27.93 MJ/m3, approximately 11-/26-foldhigher than those of neat PVA hydrogel, while tearing strength was significantly enhanced, attributed tohigh energy dissipation through unzipping multiple interactions.