This study explores the enhancement of hydrogel adhesive strength by achieving a balance between cohesion and adhesion forces. Hydrogel adhesives, known for their potential in biomedical applications such as tissue sealing and soft robotics, often suffer from low intrinsic mechanical strength due to high water content and defective network structures. The research introduces a novel double network (DN) design that combines a rigid polyvinyl alcohol (PVA) network and a flexible sodium alginate (SA) network. By adjusting the ratio of PVA to SA, a balanced cohesion-adhesion structure is achieved, resulting in a threefold increase in adhesive strength compared to non-balanced systems. The DN hydrogel adhesive exhibits excellent mechanical properties, including high tensile and compressive strength, and demonstrates robust antibacterial and cytocompatibility. These findings highlight the potential of the DN hydrogel adhesive for advanced biomedical applications.This study explores the enhancement of hydrogel adhesive strength by achieving a balance between cohesion and adhesion forces. Hydrogel adhesives, known for their potential in biomedical applications such as tissue sealing and soft robotics, often suffer from low intrinsic mechanical strength due to high water content and defective network structures. The research introduces a novel double network (DN) design that combines a rigid polyvinyl alcohol (PVA) network and a flexible sodium alginate (SA) network. By adjusting the ratio of PVA to SA, a balanced cohesion-adhesion structure is achieved, resulting in a threefold increase in adhesive strength compared to non-balanced systems. The DN hydrogel adhesive exhibits excellent mechanical properties, including high tensile and compressive strength, and demonstrates robust antibacterial and cytocompatibility. These findings highlight the potential of the DN hydrogel adhesive for advanced biomedical applications.