Neutrophil extracellular traps (NETs), a reticular structure composed of DNA fibers, histones, and antibacterial proteins released by neutrophils, can trap and eliminate foreign pathogens and play a significant role in the initiation and development of tumors. The formation and release of NETs are regulated by various factors from the tumor microenvironment, including signaling molecules released by tumor cells, inflammatory cytokines, oxidative stress, and angiogenesis. In addition, NETs interact with immune cells in the tumor microenvironment, collectively shaping the immune characteristics of the tumor microenvironment and participating in critical biological processes such as metabolic regulation of tumor cells, tumor metastasis, tumor-related thrombosis, and tumor angiogenesis, all of which impact tumor progression and patient prognosis. This review focuses on the multiple mechanisms of NETs in tumor progression, explores the mechanisms of NETs in regulating tumor cell proliferation and metastasis, altering tumor microenvironment, affecting tumor angiogenesis, immune escape, and the potential application prospect of NETs as biomarkers for diagnosis and prognosis, which reveal the significant role of NETs in tumor biology and provide a theoretical foundation for future research and clinical application.