Herein, a metal-free 1,3-dipolar cycloaddition click reaction was used to prepare hydrogels. First, copolymer of N,N-dimethylacrylamide and 2-hydroxyethyl methacrylate was synthesized via free radical copolymerization with an initiator of 2,2’-azobisisobutyronitrile and a solution of 1,4-dioxane. Second, maleimide-functionalized polymer was obtained by a coupling reaction of the above synthesized copolymer and N-maleoyl alanine with a dehydrating agent of N,N’-dicyclohexylcarbodiimide. Similarly, azido-modified polymer was prepared by the reaction between azidoacetic acid and the as-prepared copolymer. Third, the hydrogels were obtained by the reaction of the azidomodified polymer and maleimide-functionalized copolymer without any initiator or catalyst. Gelation times of different conditions were measured by a cuvette inversion method. The samples of different steps were analysized by means of FTIR, NMR, SEM, etc. The swelling behaviour of the gels was investigated via a general gravimetric method. Finally, release mechanism was explored with a model drug molecule of 5-fluorouracil. It was found temperature, concentration and solvent had an impact on the gelation time. And the swelling behavior and drug-controlled release profiles of the hydrogels were relevant to the concentration of polymers used for the hydrogels.