Abstract: Neutrophils are the most abundant leukocytes in the peripheral blood and play an important role in the immune response.However, there is growing evidence indicating that in addition to the immune response, neutrophils also have a crucial role in tumor development, especially in the process of invasion and metastasis. According to current research, depending on their phenotype, neutrophils appear to be either anti-metastasis (N1) or pro-metastasis (N2). However, the role of tumor-associated neutrophils (TANs) in the metastasis of tumors is relatively complex and lacks a systematic introduction. This review mainly introduces TANs and focuses on the mechanism of TANs in promoting tumor invasion and metastasis. Finally, the possibility of TANs as an anti-tumor treatment strategy is discussed.