4 Methyl-1-(2-N-(2-pyrrolidinonyl) ethyl) itaconate (PyEMI) was synthesized by reaction of 4 methyl itaconate chloride (MIC) with 1 (2 hydroxyethyl) 2 pyrrolidinone (HEPy). It undergoes free radical polymerization easily. The aqueous solution of P(PyEMI) shows a sensitive response against the change of temperature. The solution transmittance was dropped sharply with the increase of temperature at the transition temperature. The transition temperature was increased with the decrease of the solution concentration.The hydrogels of P(PyEMI) were prepared by polymerization of PyEMI in glass mould with ethylene glycol dimethacrylate as a cross-linker.The swelling ratio(SR) of the hydrogels were decreased with the increasing of temperature in water but increased in mixed solvent of DMF/water (4/1).