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.