In order to improve the comprehensive mechanical properties of hydrogels, a fully physically crosslinked triple interpenetrating network hydrogel was designed and studied. One-step free-radical emulsion polymerization method was used to obtain hydrophobically-associated polyacrylamide networks. Freeze-thaw cycles and immersion in FeCl₃ solution was conducted successively to form microcrystalline crosslinked polyvinyl alcohol networks and ionic crosslinked sodium alginate networks, respectively. P(AM-SMA)/PVA/SA triple interpenetrating network (HMITN) hydrogels were obtained. The structure of the hydrogels was characterized by Fourier transform infrared (FT-IR). The mechanical properties of the hydrogels were studied by electronic universal testing machine. The results show that HMITN hydrogels have excellent strength, toughness, fatigue resistance and self-recovery performance, the stress and fracture energy can reach 0.45 MPa and 2.48 MJ/m³, respectively. After 5 cycles of stretching at 200% strain, the dissipated energy of the hydrogel can maintain 20.3% with respect to the first cycle. The hydrogel could recover to 66.7% of its initial toughness after resting for 260 min.