Objective: To evaluate the superiority in diagnosing DVT between venography and duplex ultrasound, and the effectiveness of C-reactive protein (CRP) as a biomarker. Methods: Firstly,the iliac - femoral vein of the dog left hind leg was isolated,and then, the thrombosis model was established by infusing the thrombin after breaking endangium.The recanalization of thrombosis was assessed by duplex ultrasound and venography, and the expression of serum hsCRP was also examined. From 2006 to 2008, 77 patients with acute DVT proximal to the knee joint were admitted. The interval between the onset of DVT and admission was 1-21 days. They were treated mainly with urokinase and low molecular weight heparin for 2 weeks. The assessment of each patient including clinical manifestation, venography, duplex ultrasound and serum highly sensitive C-reactive protein (hsCRP) were performed immediately after admission and 4 weeks after discharge. Results: After medical therapy for 2 weeks, the clinical features prominently subsided in 49 patients, improved in 23 and didn’t ameliorate in 5.4 weeks after discharge, venography showed clot regression in 15 patients; while in the remaining 62 patients the occluded venous lumen were not visualized, duplex ultrasound showed partial lysis of the thrombosis. At admission, the hsCRP was 28.91?29.4mg/L, and it dropped to 8.13?12.7mg/L at 4 weeks after discharge. Conclusion:Duplex ultrasound was effective to assess DVT. The hsCRP was positively related to the severity of DVT.