The invention discloses an application of ropivacaine in preparation of a triple-negative breast cancer treatment drug and belongs to the technical field of medicine. The drug is medicament prepared from ropivacaine as an active ingredient and pharmaceutically acceptable auxiliary materials, and the medicament is an injection preparation. Pharmacological experiments and clinical experiments prove that the drug prepared from ropivacaine can treat the triple-negative breast cancer and has the advantages of remarkable effect, small side effect, wide therapeutic window and the like, and the drug cannot produce an after effect on a patient and can be popularized and used clinically.