Temperature sensitive polymer is a class of macromolecule compound and an intelligent polymer and their structure and physical and chemical properties mutate when the temperature changes. This paper introduces the classification of temperature sensitive polymers including such three categories as Nsubstituted acrylamic polymer, Amphiphilic block copolymer and polypeptide, by taking PNIPAAm as an example from their chain functional group composition and their respective role when temperature changes, expounds temperature sensitive mechanism of the polymers by the preparation of linear Nsubstituted acrylamide polymer, Nsubstituted acrylamide hydrogel and Nsubstituted acrylamide grafy polymer synthesis, and explains their application in life science such as drug release control, enzyme immobilization, chromatographic stationary phase and so on.