Introduction: The photo-activated thermo/gas antimicrobial nanocomposite hydrogel, Gel/PDA@BNN6, is composed of the nitric oxide (NO) carrier N, N'-di-sec-butyl-N, N'-dinitroso-p-phenylenediamine (BNN6), photothermal (PTT) material polydopamine nanoparticles (PDA NPs), and methacrylate gelatin (GelMA). This hydrogel can release NO gas in a stable and controlled manner, generating a localized photothermal effect when exposed to near-infrared laser light. This dual action promotes the healing of full-thickness skin wounds that are infected.<br /> Methods: Gel/PDA@BNN6 was developed, and both in vitro and in vivo experiments were carried out to evaluate its structure, physicochemical properties, antibacterial effects, effectiveness in promoting infected wound healing, and biocompatibility.<br /> Results: Gel/PDA@BNN6 was successfully synthesized, exhibiting a porous three-dimensional lattice structure and excellent mechanical properties. It demonstrated highly efficient photothermal conversion, controllable nitric oxide delivery, strong bactericidal effects, and minimal cytotoxicity in vitro. In vivo, Gel/PDA@BNN6, when used with NIR therapy, showed significant anti-inflammatory effects, promoted collagen deposition, and stimulated vascular neoangiogenesis, which accelerated wound closure. Additionally, it displayed superior biocompatibility.<br /> Discussion: Gel/PDA@BNN6 has shown an explicit curative effect for infected wound healing, suggesting it has a good chance of being an antimicrobial dressing in the future.