Objective To explore the diagnostic value of dual syringe and dual-channel direct multi-slice computed tomography venography(MSCTV) for lower extremity deep venous obstructive disease.Methods 100 patients highly suspected deep vein thrombosis by clinic wereunderwent dual syringe and dual-channel direct MSCTV.The original data processed with technology of subtraction,and put into workstation and reconstructed with maximum intensity projection(MIP),multiplanar reformation(MPR) and volume rendering (VR).Images of deep venous obstructive lesions were analysed and graded.All patients were underwent DSA in one week.Results Direct MSCTV showed that the reconstructed images and the vascular contrast were very clear.In the evaluation of deep venous,excellent proportion was 95 ％ for the inferior vena cava,94 ％ for the common iliac vein,95 ％ for the external iliac vein,95.5 ％ for the femoral vein,96.5％ for the popliteal vein and 92 ％ for the low leg vein.Direct MSCTV displayed complete and regular vein in 8 normal patients,92 cases displayed different parts and different degrees of thrombosis.On original axial images,eccentric filling defect of vascular were showed (there were 64 multiple vein occlusion cases and 28 solitary obstruction cases).The occlusion locations in deep venous were as following:3 in the inferior vena cava,67 in the common iliac vein,28 in the external iliac vein,50 in the femoral vein,26 in the popliteal vein,89 in the anterior tibial vein,35 in the posterior tibial vein and 5 in the peroneal vein.There were 7 normal patients and 93 patients with different parts and different degrees of thrombosis.Conclusion Direct MSCTV can accurately show deep vein thrombosis,which image is clear and reliable for displaying the scope and extent of lesions of the vascular and whether the collateral circulation established.Direct MSCTV has a significant clinical value in diagnosing the thrombotic disease of deep vein obstructive lesions.