Abstract: Breast cancer is one kind of serious diseases threatening the health of women, and there is no exact prevention method due to its unclear mechanisms. Surgery, radiotherapy and chemotherapy are the main treatment methods, unpleasantly, following with side effects and high risk. Researches show that the breast cancer stem cell(BCSC) isolated from the solid tumors, owning the ability of self-renewal and multi-directional differentiation, can mediate tumor invasion, metastasis, relapse and resist conventional radiochemotherapy, which makes an important theoretical and practical contribution on breast cancer treatment targeting on stem cells. Here in, we summarize the recent progress on the regulations and roles of breast cancer stem cells.