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A kind of terpyridine derivative (<b>NH₂-Tpy</b>) in which the amino was incorporated by a short alkyl chain was synthesized. Through grafting of terpyridine units into the hydrophilic copolymers of maleic anhydride and acrylic acid <b>PAAMa</b> via the reaction of the amino groups in <b>NH₂-Tpy</b> and the maleic anhydride units, a series of gelator polymers—<b>P1</b>, <b>P2</b>, and <b>P3</b>—containing different contents of terpyridine units was synthesized. Under coordination of Ni²⁺ and terpyridine ligands in linear polymers, the supramolecular hydrogels <b>H1</b>, <b>H2</b>, and <b>H3</b> with different cross-linking degrees were prepared. The linear polymers <b>P1</b>–<b>P3</b> had a strong absorption peak at about 290 nm in the UV-vis spectra which was attributed to π–π* transition, and there was a new peak at about 335 nm led by the metal-to-ligands charge transfer (MLCT) when coordinated with Ni²⁺ ions. According to the rheological behaviors, the storage modulus (G′) was larger than the loss modulus (G′′). These hydrogels showed typical gel-like characteristics when the terpyridine content of the hydrogels exceeded 10%, and the hydrogels showed liquid-like characteristics when the terpyridine content of the hydrogels was less than 7%. The results of the micromorphological investigation of the xerogels from SEM illustrated the metal–terpyridine coordination cross-linking could have an important influence on the microstructures of the resulting hydrogels. Furthermore, these hydrogels based on supramolecular cross-links exhibited reversible solution–gel transition at different environmental temperatures. At the same time, the equilibrium swelling of the supramolecular hydrogels was 8.0–12.3 g/g, which increased with the decrease in the content of the terpyridine units in the resulting hydrogels.