Breast cancer with ki67 of 50% is relatively serious, and tumors with ki67 of 50% are malignant tumors with a high degree of malignancy. Ki67 is an indicator for clinical evaluation of cell division ability, the stronger the division ability, the higher the malignancy of the tumor. If the Ki67 of a tumor is greater than 30%, it indicates that the tumor has a strong cell division ability, i.e., a high degree of malignancy, and is prone to local infiltration and distant metastasis, and therefore clinically considered to be at high risk. Therefore, for malignant tumors with Ki67 greater than 30%, appropriate treatment needs to be strengthened, such as intensive adjuvant chemotherapy, which can further improve the patient’s prognosis. Close postoperative follow-up is also needed to observe whether there is recurrence and metastasis, and early detection and early treatment. For patients with Ki67 of 50%, the malignancy of the tumor is high, and it is recommended that the patients go to regular hospitals, strengthen the treatment under the guidance of doctors, and pay close attention and follow-up.