Abstract: Many researches are carried out and focused on neoadjuvant therapy for breast cancer in recent years, many biomarkers are considered to be important predictors for the evaluation of neoadjuvant therapy efficacy. The proliferation marker Ki67, a component of the mitotic chromosome periphery, plays an important role in cancer research. Ki67 is essential for determining breast cancer molecular subtype and a perfect predictor of breast cancer prognosis. According to its clinical practical value, Ki67 is used to be an important evaluation index and predictors in hormone receptors positive breast cancer patients with neoadjuvant endocrine therapy. It turns out to be a primary efficacy endpoint in the clinical trial of neoadjuvant endocrine treatment, more important than other evaluation of target lesions. This review aims to elucidate the significance and the assessment guidelines of Ki67 index in neoadjuvant endocrine therapy of hormone receptors positive breast cancer.