Breast cancer is a disease that seriously endangers the health of women. However, it is difficult to treat due to the emergence of metastasis and drug resistance. Exploring the metastasis mechanism of breast cancer is helpful to aim for the appropriate target. The epithelial-mesenchymal transition (EMT) is an important mechanism of breast cancer metastasis. Sodium channel 1.5(Na1.5) and the GTPase Rac1 are factors related to the degree of malignancy of breast tumors. The expression of Na1.5 and the activation of Rac1 are both involved in EMT. In addition, Na1.5 can change the plasma membrane potential (Vm) by promoting the inflow of Na to depolarize the cell membrane, induce the activation of Rac1 and produce a cascade of reactions that lead to EMT in breast cancer cells; this sequence of events further induces the movement, migration and invasion of tumor cells and affects the prognosis of breast cancer patients. In this paper, the roles of Na1.5 and Rac1 in EMT-mediated breast cancer progression were reviewed.