Current diabetic wound treatments remain difficult in clinical due to bacterial infection and excessive reactive oxygen species (ROS). An ideal wound dressing should have prominent antibacterial and ROS scavenging abilities. In this work, a conveniently multifunctional hydrogel wound dressing (abbreviated as CuTA/SG) was constructed by incorporating copper/tannic acid nanosheets into a dynamic cross-linking network composed of oxidized sodium alginate, gelatin, and Ca2+. The resulting CuTA/SG hydrogel had excellent exudate absorption, adjustable photothermal antibacterial, and ROS scavenging features. Furthermore, CuTA/SG hydrogel was injectable that possessed excellent adaptability to adapt to the wound defects due to its appropriate physical cross-linking. Astonishingly, CuTA/SG hydrogel showed good hemostasis, antibacterial, anti-inflammation, and even hair regeneration capabilities, which can significantly promote diabetic wound healing in the full-thickness skin defect model in rats through reducing inflammation, guiding wound repair, and restoring skin physiological functions. Therefore, this study develops a simple and effective strategy for fabricating highly effective hydrogel dressing, which might provide new options for clinical wound management.