This invention provides a tumor-targeting peptide. This tumor-targeting peptide comprises a typical motif with the general formula of: XX(Y/F) (D/E) (D/E) XX. The motif is selectively connected with 1-3 amino acids at the C-terminal and/or N-terminal. X represents any one of the twenty natural amino acids or the D type amino acids. The present invention also discloses that the peptide can not only target tumor vessels and tumor cells but also penetrate them and thus can be applied in tumor diagnosis and therapy.
