Cancer-associated fibroblasts (CAFs) are mainly derived from quiescent normal fibroblasts, and partially originated from mesenchymal stem cells, epithelial cells and endothelial cells. As an important part of the tumor microenvironment (TME), CAFs play a key role in the metastatic process of breast cancer. In recent years, researchers have paid more attention to the biological properties of CAFs and their interactions with breast cancer cells, which promote breast cancer cell invasion and metastasis by secreting various cytokines and exosomal microRNA (miRNA), altering extracellular matrix compositions, regulating intercellular signaling, and remodeling the TME. Although a large number of studies have revealed the importance of CAFs in breast cancer metastasis, their specific mechanisms of action need to be further explored. In this paper, we will systematically review the latest research progress of CAFs in breast cancer metastasis, and explore the core mechanism and function of CAFs in it, with a view to providing new ideas for future research.