Abstract: Neoadjuvant chemotherapy(NAC)is one of the main strategies for patients with locally advanced breast cancer.Clinical and pathologic response rates are equivalent used for evaluating therapeutic effect.The expression of Ki-67 protein is associated with cell proliferation.It has been widely used in the diagnosis and prognosis of various tumors.A number of clinical data indicate that Ki-67 demonstrated a potential value in determining the effectiveness of neoadjuvant chemotherapy for breast cancer.The role of Ki-67 on neoadjurant chemotherapy and its clinical significance is reviewed.