Abstract: The PI3K/Akt/mTOR signaling pathway is involved in inhibiting the apoptosis of tumor cells, promoting cell survival, and regulating cell cycle, as well as in the angiogenesis, invasion, and metastasis of tumors. Therefore, this pathway has an important function in tumorigenesis, tumor growth, prognosis, and treatment. So the PI3K/Akt/mTOR signaling pathway as a new therapeutic target and has been highlighted in breast cancer research. Pre-clinical studies have confirmed that mTOR inhibitors achieve anticancer effects by targeting the PI3K/Akt/mTOR signaling pathway. Endocrine therapy is the primary method in breast cancer treatment. However, this therapy has instances of drug resistance because chemotherapy and other treatments are administered to patients. Only blocking one site point does not meet the treatment needs because more signaling pathways have been identified. Identifying a common inhibitory site for multiple pathways has become the focus of research. The mTOR inhibitor is the crossing point of multiple signaling pathways and has attracted extensive attention in this subject.