Excessive reactive oxygen species (ROS) production induces oxidative damage to biomolecules, which can lead to the development of chronic diseases. Biocompatible hydrogel antioxidants composed of natural materials, such as polysaccharides and polyphenols, are of significant option for ROS scavenging. However, rapidly achieving hydrogel antioxidants with convenient, economical, safe, and efficient features remains challenging. Herein, facile synthesis of a physically cross-linked polyphenol/polysaccharide hydrogel by introducing tannic acid microsize particles (TAMP) into a cationic guar gum (CG) matrix is reported. Combining antioxidant/photothermal properties of TAMP and mechanical support from injectable CG, the formulated TAMP/CG is explored for treating diabetic wounds. Both in vitro and in vivo assays verify that TAMP/CG can protect the cells from ROS-induced oxidative damage, which can also be strengthened by the local photothermal heating (42 °C) triggered by near-infrared light. Overall, this study establishes the paradigm of enhanced diabetic wound healing by mild hyperthermia-assisted ROS scavenging hydrogels.