The purpose of this study was to objectively assess the morbidity of post-thrombotic syndrome (PTS) in iliofemoral vein thrombosis treated with catheter-directed thrombolysis (CDT) and stenting under the protection of inferior vena cava (IVC) filter. All patients with an unprovoked episode of iliofemoral vein thrombosis combined with iliac vein compression syndrome (IVCS) during January 2011 and January 2015 were enrolled. Clinical records of all patients were evaluated. Firstly, cox regression was performed to find out the factors impacted the incidence of PTS. Then, Kaplan Meier analysis was conducted to verify the roles of these factors in PTS. A total of 247 patients who underwent CDT and IVC filter insertion for iliofemoral vein thrombosis and were found stenosis in the iliac vein after CDT were included in this study. Among them, 74 patients suffered PTS diagnosed via Villalta scale. Comparison with patients without stent implantation and filter withdrawal, patients with stent implantation and filter withdrawal had a less risk of PTS, but patients with a lesion in the left or bilateral proximal deep vein had a more risk of PTS. Cox regression found that stent implantation was a preventive measure to prevent PTS (OR 0.541, 95% CI 0.334-0.876, p = 0.012). The Kaplan-Meier curve found that patients with stent implantation had a less ratio of PTS occurrence (P = 0.008). In patients with iliofemoral vein thrombosis and IVCS, stent implantation to solve the residual obstruction after CDT might play an important role in preventing PTS.