A periodically ordered interconnecting porous structure could be imprinted in thermosensitive hydrogels by using silica colloidal crystals as mesoscopically sized templates. The interconnecting porous structure provides a fast response to the change in temperature for reversible swelling and shrinking of the hydrogels, while the periodically ordered mesoscopical structure endows a structural color to the gel. The structural color imprinted in the gel is quickly synchronized with the change in the volume of the gels; The newly invented mesoporous hydrogels possess optical properties as temperature sensitive smart gels.