The invention relates to a method for preparing chemically crosslinked photonic crystal hydrogel with an adjustable color. The method comprises the following steps: (1) dissolving N-isopropylacrylamide, N-hydroxyethyl acrylamide, a cross-linking agent and an emulsifier into deionized water, stirring, warming and keeping warm under the condition at 20-25 DEG C in a nitrogen condition, and then adding an initiator to continue to react for 1-4 hours, and dialyzing, so as to obtain a colloidal crystal hydrogel solution; (2) concentrating the obtained colloidal crystal hydrogel solution, standing at room temperature, adjusting the pH by adopting an NaOH solution, adding a crosslinking agent, evenly mixing, centrifuging, and standing at room temperature after taking, so as to obtain the chemically crosslinked photonic crystal hydrogel. The method is simple in process and low in cost, and the prepared photonic crystal hydrogel has thermosensibility. In addition, the obtained photonic crystal hydrogel is good in stability, and free of hydrolysis, the problem that nano hydrogel is easily decomposed because of ester hydrolysis in 2-hydroxy ethyl acrylate is solved, and the defects of the photonic crystal hydrogel in application are compensated.