Abstract: The radiation polymerization of N-isopropylacrylamide (NIPAAm) and the radiation copolymeri-zation of NIPAAm and N-acryloxysuccinimide(NASI) in aqueous solution are carried out by γ-60Cosource at room temperature. The optimum dose range is (0. 5 - 20 kGy), and the dose rate is (30 -90 Gy/min). The monomer, crosslinking concentrations are chosen. The synthesized hydrogels and copolymer hydrogels have obvious temperature sensitivity, homogeneity, and suitable mechanical properties. In addition, an active ester group is introduced into the hydrogels through radiation copolymer-ization of NIPAAm and NASI which has good temperature sensitivity. A protein, BSA is immobilized through conjugation reaction onto the activated temperature sensitive hydrogel. The conjugation yield of BSA increased with increasing of ratio of NASI in copolymer of NIPAAm and NASI.