Provided in the present invention are a YAP protein inhibiting polypeptide and application thereof. In particular, the present invention obtains a key binding site of YAP protein and TEAD, screens a polypeptide with best YAP inhibitory activity and modifies the polypeptide, such as adding a disulfide linkage, replacing an amino acid, removing and/or adding (for example, adding a cell-penetrating element), and finally screens and verifies the obtaining of a series of polypeptides with YAP protein activity inhibiting effect and good stability. Experiments show that the polypeptide of the present invention can effectively inhibit the binding activity between YAP protein and TEAD, thus providing good therapeutic effect on digestive tract tumors (especially liver cancer).