A controlled-release hydrogel loaded with magnesium-based nanoflowers synergizes immunomodulation and cartilage regeneration in tendon-bone healing. The study developed a temperature-sensitive composite hydrogel containing magnesium-Procyanidin (Mg-PC) nanoparticles, which were integrated into a two-component hydrogel composed of dopamine-modified hyaluronic acid (Dop-HA) and F127. The hydrogel was designed to provide sustained release of magnesium ions (Mg²⁺) and Procyanidins, which promote mesenchymal stem cell recruitment, reduce inflammation, and enhance macrophage polarization toward the M2 phenotype. The hydrogel also supports collagen synthesis and mineralization, facilitating tendon-bone interface repair. The Mg-PC nanoparticles were crosslinked with the hydrogel through coordination bonds, extending the release window of Mg²⁺ concentrations up to 56 days. The hydrogel exhibited favorable properties, including injectability, thermosensitivity, and shape adaptability, making it suitable for injection and adaptation to irregularly shaped supraspinatus implantation sites. The hydrogel's multilevel metal-phenolic networks (MPN) enabled controlled ion release, enhancing its potential for various biomedical applications. The hydrogel demonstrated anti-inflammatory and antioxidant properties, creating a protective environment for stem cells during tendon-bone healing. It also modulated the immune microenvironment and promoted cartilage regeneration by facilitating stem cell migration, adhesion, proliferation, and differentiation at the injury site. The hydrogel's dual-action approach showed promise for promoting tendon-bone inter-healing, with magnesium ions facilitating cartilage matrix production through the upregulation of hypoxia-inducible factor-1α (Hif-1α). The hydrogel's mechanical properties, including tensile strength, were evaluated, with the 10% Mg-PC@Dop-HA/F127 group showing the best performance. The hydrogel's ability to control Mg²⁺ and Procyanidin release, combined with its biocompatibility and self-healing properties, makes it a promising candidate for tendon-bone healing applications.A controlled-release hydrogel loaded with magnesium-based nanoflowers synergizes immunomodulation and cartilage regeneration in tendon-bone healing. The study developed a temperature-sensitive composite hydrogel containing magnesium-Procyanidin (Mg-PC) nanoparticles, which were integrated into a two-component hydrogel composed of dopamine-modified hyaluronic acid (Dop-HA) and F127. The hydrogel was designed to provide sustained release of magnesium ions (Mg²⁺) and Procyanidins, which promote mesenchymal stem cell recruitment, reduce inflammation, and enhance macrophage polarization toward the M2 phenotype. The hydrogel also supports collagen synthesis and mineralization, facilitating tendon-bone interface repair. The Mg-PC nanoparticles were crosslinked with the hydrogel through coordination bonds, extending the release window of Mg²⁺ concentrations up to 56 days. The hydrogel exhibited favorable properties, including injectability, thermosensitivity, and shape adaptability, making it suitable for injection and adaptation to irregularly shaped supraspinatus implantation sites. The hydrogel's multilevel metal-phenolic networks (MPN) enabled controlled ion release, enhancing its potential for various biomedical applications. The hydrogel demonstrated anti-inflammatory and antioxidant properties, creating a protective environment for stem cells during tendon-bone healing. It also modulated the immune microenvironment and promoted cartilage regeneration by facilitating stem cell migration, adhesion, proliferation, and differentiation at the injury site. The hydrogel's dual-action approach showed promise for promoting tendon-bone inter-healing, with magnesium ions facilitating cartilage matrix production through the upregulation of hypoxia-inducible factor-1α (Hif-1α). The hydrogel's mechanical properties, including tensile strength, were evaluated, with the 10% Mg-PC@Dop-HA/F127 group showing the best performance. The hydrogel's ability to control Mg²⁺ and Procyanidin release, combined with its biocompatibility and self-healing properties, makes it a promising candidate for tendon-bone healing applications.