Lignin-containing cellulose nanofiber (LCNF)-based hydrogels are promising eco-friendly biomaterials, yet the role of lignin in enhancing their adhesion and mechanics remains to be explored. Herein, quaternized lignin-containing cellulose nanofibers (QALCNFs) with varying lignin contents were synthesized from bagasse using a deep eutectic solvent (DES). The relationship between lignin content and the adhesion and mechanical properties of QALCNF hydrogels was systematically investigated. Results demonstrated that lignin in QALCNFs enhanced the hydrogel's gelation time, adhesion and mechanical properties through the provision of quinone/catechol groups, which undergo reversible free radical transformations. As the lignin content decreased, the nanofiber bundles gradually transitioned into more uniform nanofibers, forming a hydrogel with a hierarchical porous structure, superior adhesion, and mechanical properties. Conversely, insufficient lignin content weakened the hydrogel's performance by reducing the quinone/catechol content and decreasing hydrogel porosity. Consequently, QAMLCNF-H exhibited outstanding toughness (2400 J/m