Objective To analyze inducing factors and clinical characteristics of deep venous thrombosis (DVT) and to explore clinical value of soluble cell surface differentiation antigen 40 ligand (sCD40L) in early diagnosis of DVT. Methods The patients with the DVT of lower extremity who had not received the anticoagulant and thrombolytic therapy in the Nanchong Central Hospital from January 2012 to January 2017 were collected, these patients were divided into an early-acute stage, mid-acute stage, late-acute stage, and subacute stage according to the clinical course of DVT. The sCD40L expression in the peripheral blood of DVT patients were detected by the enzyme linked immunosorbent assay. Results There were 100 patients with the DVT were included, including 31 cases of early-acute stage, 26 cases of mid-acute stage, 21 cases of late-acute stage, and 22 cases of subacute stage; 66 patients with the peripheral type, 28 patients with the central type, and 6 patients with the mixed type. ① The fracture, malignant tumor, long time in the bed following the thoracic or abdominal operation, joint replacement, and caesarean section were the successively main risk factors of the DVT. ② The early-acute stage of DVT was more common in the fracture patients, the mid- and late-acute stage of DVT often occurred in the joint replacement sufferer, and the subacute stage of DVT was usually found in the malignant tumor patients. ③ The sCD40L expression in the patients with the different stage DVT was signifiantly higher than that in the control group (20 healthy people in the physical examination, P<0.05). Furthermore, there was a significant difference in the different stage DVT patients (F=26.57, P=0.02), that is, the expression of sCD40L was the highest in the early-acute stage of DVT, and then gradually reduced (P<0.05). ④ The sCD40L expression had a significant difference among the central type DVT, mixed type DVT, and peripheral type DVT (F=12.51, P=0.02), which in the peripheral type DVT was significantly higher than that of the central type DVT (P<0.05) and mixed type DVT (P<0.05), but had no difference between the central type DVT and the mixed type DVT (P>0.05). ConclusionsCD40L might act as a blood index of early diagnosis and judgement of extent of DVT, especially be helpful in early-acute stage of DVT.