biodegradable copolymer hydrogels are provided . the biodegradable copolymer hydrogels have a structure of formula or formula a - b — box — b - a formula b - a - b — n - box — b - a - b formula , wherein , a comprises a hydrophilic polyethylene glycol polymer ; b comprises a hydrophobic polyester polymer ; box is bifunctional group monomer of 2 , 2 ′- bis and used for coupling the blocks a - b or b - a - b ; and n is an integer , equal to or greater than 0 .