A novel anisotropic hydrogel, consisting of lamellar bilayers and a polymer network, with unidirectional alignment of the bilayer structure has been synthesized. The unidirectional orientation of bilayer in the gels leads to one-dimensional swelling, strong anisotropy in elastic modulus, and exhibits excellent visible color. The gel shows reversibly tunable structural color under mechanical stimulation and could be the basis for a deformation-based color display.