Hydrogel　is　widely　employed　in　flexible　electronics　and　soft　robotics　as　soft　mechanical　material.　Previous　reports　exploited　the　swelling　properties　of　hydrogel　to　achieve　large　negative　deformations,　but　few　reports　exhibit　multiple　deformation　modes.　This　paper　designs　two-dimensional　metamaterials　that　convert　hydrogel　swelling　deformation　into　bending　deformation,　including　positive/negative　swelling,　isotropic/anisotropic,　and　gradient/bending　deformation　modes.　The　regulation　of　hydrogel　swelling　on　the　negative　expansion　deformation　of　metamaterials　is　explored　through　the　theoretical　model　and　finite　element　analysis.　The　corresponding　relationship　between　the　microstructure　deformation　and　the　band　gap　change　during　the　hydration　process　is　obtained.　Inspired　by　kirigami,　we　proposed　a　self-assembly　model　with　substrate　expansion-driven　three-dimensional　microstructure.　The　results　show　that　the　deformation　modes　of　metamaterials　may　be　interconverted　through　structural　design.　The　band　gap　can　be　tuned　by　swelling　deformation.　©　2024