The invention relates to the field of responding type injectable hydrogels, in particular to a dipeptide hydrogel, a preparation method and application thereof. A dipeptide molecule is of an XY structure, wherein X is selected from tyrosine, phenylalanine, tryptophan or histidine; Y is selected from aspartic acid, asparagine, glutamic acid or glutamine. The hydrogel has a quick ultrasonic response characteristic, can be quickly recovered to a gel state after stimulating response, is stable and uniform in properties, and can be applied to the fields of biological nano-materials, medicament controlled-release, medicament delivery, cell encapsulation and tissue repair.