Postoperative peritoneal adhesion are serious clinical complications. Various hydrogel barriers have been developed to prevent peritoneal adhesion. However, it remains a challenge to design a hydrogel with desirable physicochemical properties and bioactivities. In this study, we developed a zwitterionic polysaccharide‐based multifunctional hydrogel using epigallocatechin‐3‐gallate (EGCG) to prevent postoperative abdominal adhesion. This hydrogel is simple to use and has desirable properties, such as excellent injectability, self‐healin and nonswelling properties. The hydrogel also has ultralow fouling capabilities, such as superior bactericidal performance, cell and protein adhesion, and low immunogenicity resistance. Moreover, the hydrogel exhibited good antioxidant activity, which was attributed to the integration of EGCG. Furthermore, the detailed mechanism from in vivo and in vitro experimental studies illustrates that hydrogel compositions can synergistically prevent adhesion formation through multiple pathways, including anti‐inflammatory and antioxidant capabilities and inhibition effects on the mesothelial‐mesenchymal transition process induced by transforming growth factor (TGF‐β). In summary, this zwitterionic multifunctional hydrogel has great potential to prevent postoperative adhesion formation in the clinical setting.This article is protected by copyright. All rights reserved