Breast cancer is the most common female malignant tumor in China. In the treatment of breast cancer, traditional Chinese medicine (TCM) and its extracts have become a research hotspot because of their characteristics of single drug but multiple targets and low toxicity. Norcantharidin is a novel synthetic anti-cancer drug which can also raise the level of leukocytosis. Its mechanism includes anti-angiogenesis, fueling cancer cell apoptosis, inhibiting cancer cell proliferation, invasion and metastasis. Chinese patent medicines with cantharidin as the main source have been used throughout the whole clinical treatment of breast cancer. In this article, we mainly reviewed the research of norcantharidin in breast cancer in the last few years.