Crossing linker was an indispensable component in the preparation of the hydrogel and its composition and structure influenced the properties and applications of hydrogels. Biodegradability and biocompatibility were essential properties of biomedical materials applied as drug carriers and tissue engineering scaffolds. The biodegradable agent as crossing linker could endow the hydrogel with biodegradability and biocompatibility and meet the requirements as biomedical materials. In this paper

the synthesis and application of natural and synthetic biodegradable polymer crossing linkers such as polysaccharide

polyester

poly(amino acid) were summarized. The development of the future biodegradable polymer crossing linker was also proposed.