Postoperative peritoneal adhesion, driven by inflammatory response and fibrotic deposition, remains the most common complication following abdominal surgeries, with limited effective solutions. Herein, a dual-network hydrogel patch (GPSB) is developed for effective peritoneal adhesion prevention through interpenetrating a gelatin network with a zwitterionic polysulfobetaine (PSB) network. The biodegradable gelatin network is dynamically crosslinked via zinc ion (Zn2+)-polyphenol coordination, endowing the patch with inherent antibacterial and pro-healing activities. Through in situ polymerization, a crosslinked PSB network is interwoven with the gelatin matrix, markedly increasing the Young's modulus of hydrogels to 97.7±5.2 kPa and greatly enhancing their mechanical integrity. Moreover, the resulting GPSB hydrogel achieves a shear strength of 28.5 kPa, on par with commercial cyanoacrylate-based bio-glues. Moreover, the highly biocompatible PSB component effectively resists nonspecific protein adsorption by 46-fold and modulates macrophage-mediated inflammatory responses, reducing the secretion of inflammatory cytokines by approximately 70%. Through the synergistic antibacterial and anti-inflammatory functions, the GPSB hydrogel patch provides robust protection against postoperative inflammation and achieves efficient prevention of peritoneal adhesions. This study highlights an effective and multifunctional hydrogel patch for next-generation anti-adhesion biomaterials.