Breast cancer Ki67 positivity rate of 30% is considered high expression, a single indicator suggests a high risk of recurrence, but also need to be combined with staging, molecular typing and other judgment. Ki67 is a tumor proliferation-related indicator, generally 20% as the high and low expression threshold, breast cancer 15% as the threshold. Breast cancer Ki67>15% is high expression, suggesting that the tumor proliferation is active, the degree of malignancy is high, and the risk of recurrence and metastasis is high. Breast cancer Ki67 positive rate of 30% belongs to high expression, in terms of this indicator, the tumor is poorly differentiated, and has a higher risk of recurrence and metastasis. However, the risk of breast cancer recurrence is related to tumor stage, molecular typing, histological grading and other indicators, and the single Ki67 is only one of the influencing factors. Generally speaking, the low recurrence risk is satisfied with no lymph node metastasis, tumor ≤2cm, histological grade I, hormone receptor positive and human epidermal growth factor receptor 2 (HER2) negative, and Ki67 ≤15%, while the medium-high recurrence risk is satisfied with lymph node metastasis, larger tumor volume, higher histological grade, hormone receptor negative, HER2 positive, and so on. It is recommended that patients combine the staging, grading, and molecular typing of the tumor to comprehensively determine the risk of recurrence. However, even assessing the recurrence risk and the high or low recurrence rate does not necessarily mean that the tumor will or will not recur, and patients should actively adjust their mindset to cooperate with the treatment.