The prognosis of luminal B breast cancer with a Ki-67 index of 30% is relatively good. luminal B breast cancer is defined as molecularly typed hormone receptor (estrogen receptor and progesterone receptor) positive and/or HER2 positive breast cancer, which has a poorer prognosis than luminal A, but better than HER2 positive breast cancer and triple negative breast cancer alone. In the clinic, doctors need to do risk stratification by determining the prognosis of breast cancer, and make treatment plan according to the recurrence risk of patients, consider the factors of endocrine therapy including hormone receptor expression and menopausal status, consider whether chemotherapy needs to be combined with the results of multigene testing, the number of lymph node metastasis, and consider whether targeted therapy needs to take into account the HER2 status. The prognosis can only be maximized by giving appropriate treatments for different risks. It is recommended to follow the doctor’s advice and actively cooperate with the treatment to improve the prognosis.