Neutrophil extracellular traps (NETs) are promising promoters in venous thromboembolism (VTE). In the present study, we have investigated the potential thrombogenic role of NETs in colorectal cancer (CRC). A total of 583 patients with gastrointestinal malignancies who were diagnosed with or without VTE by extremities arteriovenous ultrasound and computed tomography were enrolled. The incidence of VTE in CRC was as high as 17.53%. In serological ELISA experiments, Cit-H3, MPO and cfDNA were significantly overexpressed in CRC patients with VTE compared to CRC patients without VTE and healthy individuals. Neutrophils from CRC patients with VTE produced appreciable amounts of NETs after stimulation with phorbol-12-myristate-13-acetate, which were lacking in CRC patients without VTE and healthy individuals. CfDNA was positively correlated with plasmin-α2-antiplasmin complex and tissue plasmin activator inhibitor-1 complex, and Cit-H3 was positively correlated with plasmin-α2-antiplasmin complex, suggesting that NETs are associated with increased fibrinolytic activity. We screened some NETs-related genes by analysing several high-throughput sequencing datasets of VTE and NETs. FCGR1A was identified as the optimal target gene by pan-cancer expression analysis and survival analysis. FCGR1A was significantly overexpressed in the peripheral blood of CRC patients without VTE compared to healthy individuals and showed a positive correlation with cfDNA. Neutrophil-derived NETs were significantly reduced by FCGR1A inhibitor exposure. These findings indicate that NETs are actively involved in VTE in CRC. NETs are promising thrombotic marker and therapeutic target in CRC to prevent the thrombotic consequences of cancer.