Thiol-Michael addition reaction has become one of the most popular reaction methods in the field of synthesis of biomedical polymer materials due to the advantages of mild conditions, rapid, efficient in recent years. Well defined thermosensitive polymers poly(PEGDA-alt-EDT) were prepared by thiol-Michael addition reaction between poly(ethylene glycol) diacrylates (PEGDA) and 2,2’-(ethylenedioxy)diethanethiol (EDT). These copolymers aqueous solution exhibit a lower critical solution temperature (LCST), which can be easily tuned by the length of PEG units. These thermosensitive polymers bear acryloyloxy and thiol reactive groups demonstrated by 1H NMR spectrum and molecular weight measured by GPC. The thermosensitive poly(PEGDA-Alt-EDT) hydrogel was further formed coupling-polymerization between the end functional groups of PEG copolymers under the initiation of APS. The results of SEM, rheology and equilibrium swelling coefficient show that the poly(PEGDA-Alt-EDT) hydrogel has a typical 3D microporous structure, hydrogel rheological properties, swelling capacity and temperature responsiveness.