Circulating tumor cells are an important poor prognostic factor for breast cancer patients. Without considering optimal surgery, adjuvant radiotherapy, hormone therapy, and chemotherapy, approximately 30% of patients with limited breast cancer eventually develop distant metastasis, which is mainly caused by early transmural seeding of tumor cells. Therefore, early detection of circulating tumor cells in the peripheral blood of breast cancer can help to detect subclinical metastases at an early stage, thus helping to guide clinical treatment and determine prognosis. The existing clinical tests such as axillary lymph node status, primary focus size, tumor histological grade, hormone receptor status, etc. cannot accurately predict the recurrence and metastasis of patients; it is often too late to rely on clinical manifestations of tumor spread or conventional imaging methods to diagnose tumor metastasis.