As an important component of innate immune system, the neutrophil is involved in many physiological processes, including tumor-related diseases. In 2004, the phenomenon of NETs, network structures of extracellular decondensed chromatin released from activated neutrophils, was reported for the first time. This review focuses on the function of NETs in tumor cell proliferation, metastasis, and tumor-associated thrombosis; it also explores the application of NET specific markers in the diagnosis of pre-thrombotic state and tumor associated diseases; the potential of NET inhibitor for the treatment of tumor-related diseases is also covered. In view of the rapid development of NETs, it may provide new therapeutic targets for tumor-associated thrombosis, and even tumors themselves.