Abdominal and intrauterine adhesions are common postoperative problems that can cause serious complications. Current adhesives are usually double sided and suffer from poor wet adhesion, nondegradability, and monofunctionality, which limits their application in preventing postoperative adhesions. Herein, a bioinspired microstructured Janus bioadhesive, named OD/GM@PG, with a wet adhesive inner layer and an antiadhesive outer layer is prepared by combining electrostatic spun and adhesive materials. By using both capillary suction and a catechol-based strategy, the wet adhesive strength and interfacial toughness of the Janus bioadhesive reach 98 kPa and 325 J m−2, respectively, which are much higher than those of commercial fibrin glues and cyanoacrylate glues. The electrostatic spun outer layer acts as a physical barrier with antiadhesive and friction-reducing effects. Additionally, the Janus bioadhesive demonstrates biodegradable, hemostatic, antioxidative, anti-inflammatory, and prohealing properties. In vivo results show that the asymmetric adhesion effect of the Janus bioadhesive effectively preventing postoperative abdominal and intrauterine adhesions. Notably, tandem mass tags-labeled quantitative proteomics analysis demonstrate that the expression of inflammatory response-associated proteins (S100A8, S100A9) is associated with adhesion; the Janus bioadhesive significantly downregulates this expression. Therefore, the OD/GM@PG Janus bioadhesive is a promising candidate for preventing postoperative adhesions.