Objective:To investigate the risk factors of venous thromboembolism (VTE) in patients with severe traumatic brain injury (TBI).Methods:A retrospective case-control study was conducted for clinical data of 180 severe TBI patients admitted to West China Hospital, Sichuan University from July 2019 to July 2021, including 137 males and 43 females, aged 18-93 years [(50.8±18.2)years]. Glasgow Coma Scale (GCS) was 3-8 points [4 (3, 6)points].VTE was presented in 95 patients (thrombosis group), but was not seen in 85 patients (non-thrombosis group). Univariate analysis was used to detect the correlation of the following data with the occurence of VTE, inlcuding sex, age, body mass index (BMI), hypertension, diabetes, laboratory indicators measured on admission and at days 3-5 after admission [hemoglobin (Hb), platelet counts (PLT), antithrombin III, prothrombin time (PT), thrombin time (TT), activated partial thromboplastin time (APTT), fibrinogen (FIB), D-dimer (D-D)], tracheal intubation or not, operation or not, volume of intraoperative blood transfusion, operation time, anesthesia time, admission to ICU or not, mechanical ventilation or not, pharmacological prophylaxis or not, deep venous catheterization or not, parenteral nutrition or not, tracheal intubation time, tracheotomy or not, pneumonia, stress ulcer, blood transfusion or not and hospital stays. Multivariate Logistic regression analysis was used to identify the independent risk factors for VTE.Results:Univariate analysis showed that the occurence of VTE was correlated with sex, laboratory indicators measured on admission (TT, FIB, D-D), tracheal intubation, operation, intraoperative blood transfusion, operation time, anesthesia time, admission to ICU, mechanical ventilation, laboratory indicators measured at days 3-5 after admission (PLT, TT, FIB, D-D), deep venous catheterization, parenteral nutrition, tracheal intubation, tracheotomy, pneumonia, blood transfusion and hospital stays (all P<0.05 or 0.01), not with age, BMI, hypertension, diabetes, laboratory indicators measured at admission (Hb, PLT, antithrombin III, PT, APTT), laboratory indicators measured at days 3-5 after admission (Hb, antithrombin III, PT, APTT), pharmacological prophylaxis and stress ulcer (all P>0.05). Multivariate Logistic regression analysis showed that higher FIB on admission ( OR=1.27, 95% CI 1.04-1.56, P<0.05), tracheal intubation ≥7 days ( OR=2.98, 95% CI 1.40-6.33, P<0.01), tracheotomy ( OR=2.49, 95% CI 1.11-5.60, P<0.05), blood transfusion ( OR=2.75, 95% CI 1.25-6.06, P<0.05) and hospital stays >14 days ( OR=3.05, 95% CI 1.36-6.85, P<0.01) were significantly related to the occurence of VTE. Conclusion:Higher FIB on admission, tracheal intubation ≥7 days, tracheotomy, blood transfusion and hospital stays >14 days are independent risk factors for the occurence of VTE in severe TBI patients.