Hydrogel is a polymer material formed by hydrophilic polymer chain with 3 D network structure and with strong water absorption and water retention; starch is an environmentally friendly natural polysaccharide. The starch-based hydrogel prepared with starch as the substrate has good biocompatibility, strong biodegradability, and excellent solvent absorption capacity. This paper first briefly describes the common starch modification methods, including physical modification, chemical modification, enzyme modification and compound modification. Then the preparation and application of starch-based hydrogel: the preparation method of starch-based hydrogel includes chemical cross-linking, reversible physical cross-linking; it has been widely used in biological sensors, medical dressings, drug transport carriers, tissue engineering stents, agricultural soil protection, how to improve the functionality of starch-based hydrogel. Finally, the development direction of starch-based hydrogel, such as the green development of crosslinking agents and initiators, the introduction of dual network, and the expansion of composite functions such as conductivity and antibacterial, is discussed.