Human skin exhibits highly nonlinear elastic properties that are essential to its physiological functions. It is soft at low strain but stiffat high strain, thereby protecting internal organs and tissues from mechanical trauma. However, to date, the development of materials to mimic the unique mechanical properties of human skin is still a great challenge. Here wereportabioinspireddesign ofnanostructured elastomerscombiningtwo abundant plant-based biopolymers, stiff cellulose and elastic polyisoprene (natural rubber), to mimic the mechanical properties of human skin. The nanostructured elastomers show highly nonlinear mechanical properties closely mimicking that of human skin. Importantly, the mechanical properties of these nanostructured elastomers can be tuned by adjusting cellulose content, providing the opportunity to synthesize materials that mimic the mechanical properties of different types of skins. Given the simplicity, efficiency,andtunability,thisdesignmayprovide apromising strategyforcreatingartificialskin forbothgeneral mechanicalandbiomedicalapplications