The efficacy of chemotherapy for triple-negative breast cancer with a low Ki-67 index is relatively poor, and the efficacy of chemotherapy depends on other molecular typing, as well as the sensitivity of the patient to chemotherapy. Ki-67 index is a marker used to reflect the proliferation status of tumor cells, which is closely related to tumor occurrence, infiltration, implantation and metastasis. The higher its value, the higher the proliferative activity of tumor cells, the higher the degree of malignancy, and the worse the prognosis. In studies of neoadjuvant therapy for breast cancer, the Ki-67 index before neoadjuvant chemotherapy was found to predict the efficacy of neoadjuvant chemotherapy. Those with a high Ki-67 index had a higher rate of pathologic complete remission (i.e., complete removal of tumor cells by chemotherapy) compared to those with a low Ki-67 index. This also reflects the fact that people with low Ki-67 index are not sensitive to chemotherapy. It is recommended to follow medical advice, actively cooperate with the treatment, improve treatment compliance, and do not discontinue the drug privately, which may cause adverse consequences.