Abstract: Epithelial-mesenchymal transition (EMT) refers to the transition during which epithelial cells undergo the loss of apical-basal polarity, acquisition of migration capability and transformation into mesenchymal cells. EMT induces breast cancer in situ to developing into metastasis and associates with the drug resistence. The multiple elements including signal pathways, transcriptional factors and downstream genes orchestrate the transition. Among them, the transforming growth factor β (TGF-β) signaling pathway plays a key role in the regulation of EMT in breast cancer. And this paper reviews the development of TGF-β signaling pathway induced EMT in breast cancer.