The invention relates to an
integrin ligand and application thereof, and particularly provides a compound shown in a formula I or a stereoisomer thereof or a pharmaceutically acceptable salt thereof, or an alpha v beta 6
integrin ligand which comprises the compound shown in the formula I or the stereoisomer thereof or the pharmaceutically acceptable salt thereof. The compounds or the [alpha] v [beta] 6
integrin ligands have good serum stability and affinity for integrin [alpha] v [beta] 6, and can be used to deliver transported molecules, such as RNAi agents, or other
oligonucleotide-based compounds to cells expressing integrin [alpha] v [beta] 6, thereby promoting
ingestion of the transported molecules to the cells.