Chronic wounds fail to heal in a timely manner due to disruption of the normal healing process, among which bacterial biofilm formation is a major barrier. Inhibiting biofilms while promoting wound repair has important clinical significance. Traditional antibacterial dressings often suffer from uncontrolled antibiotic release, and excessive antibiotic use can lead to drug resistance and additional health risks. Polyvinyl alcohol (PVA)-based hydrogels have attracted considerable attention because of their good biocompatibility and ability to maintain a moist wound environment; however, pure PVA hydrogels show limited bioactivity and insufficient functionality for biomedical applications. To overcome these limitations, a chemically/physically double-crosslinked hydrogel was constructed using PVA as the matrix and phenylboronic acid-terminated polyethylene glycol (PEG) as a functional component. Vancomycin hydrochloride (Van) was further loaded to obtain a pH-responsive antibacterial hydrogel dressing. The introduction of PEG regulated the crosslinking density and improved swelling, water absorption, and retention properties, while dynamic boronated ester bonds between phenylboronic acid and PVA hydroxyl groups endowed the hydrogel with pH responsiveness. In the weakly acidic microenvironment of bacterial biofilms, the hydrogel enabled controlled drug release and enhanced antibacterial efficacy. The prepared hydrogel exhibited excellent swelling, adhesion, and moisture-retention ability, as well as significant antibacterial activity against Staphylococcus aureus, indicating its potential as a promising wound dressing for chronic wound treatment.