Background Catheter-directed thrombolysis (CDT) for deep venous thrombosis (DVT) of the lower extremity has good effect,but whether iliac vein stent placement after thrombolytic therapy is still controversial.The goal of this study was to evaluate the efficacy of stent placement in the iliac vein following CDT in lower extremity DVT.Methods This was a single-center,prospective,randomized controlled clinical trial.After receiving CDT,the major branch of the distal iliac vein was completely patent in 155 patients with lower extremity DVT,and 74 of these patients with iliac vein residual stenosis of ＞50％ were randomly divided into a control group (n=29) and a test group (n=45).In the test group,stents were implanted in the iliac vein,whereas no stents were implanted in the control group.We evaluated the clinical indicators,including patency of the deep vein,C in CEAP classification,Venous Clinical Severity Score (VCSS),and Chronic Venous Insufficiency Questionnaire (CIVIQ) Score.Results All patients had postoperative follow-up visits for a period of 6-24 months.Venography or color ultrasound was conducted in subjects.There was a significant difference between the patency rate at the last follow-up visit (87.5％ vs.29.6％) and the 1-year patency rate (86.0％ vs.54.8％) between the test and control groups.The change in the C in CEAP classification pre-and post-procedure was significantly different between the test and control groups (1.61±0.21 vs.0.69±0.23).In addition,at the last follow-up visit,VCSS and CIVIQ Score were both significantly different between the test and control groups (7.57±0.27 vs.0.69±0.23; 22.67±3.01 vs.39.34±6.66,respectively).Conclusion The stenting of iliac vein obstruction following CDT in lower extremity DVT may increase the patency of the deep vein,and thus provides better efficacy and quality of life.