The present invention discloses a color hydrogel and a preparation method thereof. The color hydrogel mainly comprises a surfactant and water, does not contain a polymer component, and has a sandwich type ordered layered structure formed mainly from double molecule membrane/water layer/double molecule membrane, wherein the surfactant comprises a nonionic surfactant. The preparation method comprises: dispersing the nonionic surfactant in water at a temperature of 55-80 DEG C, standing for more than or equal to 24 h, and cooling to a room temperature so as to obtain the target product. According to the present invention, the color hydrogel does not contain the polymer, only comprises the surfactant, has good biocompatibility, and has good application prospects in the fields of optics, nanometer material synthesis and biology, the preparation process is simple, and the color can be regulated.