Background and Aims Iliac vein stenting (IVS) can effectively relieve the venous outflow obstruction of the left lower extremity and reduce the incidence of chronic venous insufficiency. However, stent occlusion after IVS is still inevitable. Therefore, this study was conducted to investigate the factors for stent occlusion in patients with lower extremity venous diseases after IVS.Methods The clinical data of 183 patients undergoing IVS in the Department of Vascular Surgery of Hainan General Hospital from March 2015 to August 2020 were collected. The risk factors for stent occlusion in patients were screened by univariate and multivariate Logistic regression analysis, and the predictive efficacy of each risk factor was evaluated using the receiver operating characteristic (ROC) curve.Results A total of 183 patients were included. Of the patients, 47 cases had non-thrombotic iliac vein compression syndrome (NIVCS), 92 cases had acute deep venous thrombosis of the lower extremity (DVT), and 44 cases had post-thrombotic syndrome (PTS). The primary patency rates of NIVCS patients, lower limb DVT patients and PTS patients at 12 months after IVS were 89.4%, 81.5%, and 54.5%, respectively. Results of univariate showed that stent across the inguinal ligament, incomplete coverage of the lesion, postoperative collaterals, inflow thrombus, multiple stent placement, and length of the stent were significantly associated with the occurrence of stent occlusion (all P<0.05); results of multivariate Logistic regression analysis showed that incomplete coverage of the lesion (OR=2.503, 95% CI=1.144-5.477, P=0.022) and presence of postoperative collaterals (OR=2.506, 95% CI=1.155-5.436, P=0.020) were independent risk factors for stent occlusion. ROC curve showed that the area under the curve (AUC) for incomplete lesion coverage was 0.623 (95% CI=0.522-0.725, P=0.015), with a sensitivity of 45.2% and specificity of 79.4%. The AUC for the presence of postoperative collaterals was 0.607 (95% CI=0.506-0.707, P=0.036), with a sensitivity of 47.6% and specificity of 73.8%.Conclusion The possibility of stent occlusion after IVS is increased in patients with incomplete coverage of the lesion and the presence of postoperative collaterals, for whom, follow-up should be strengthened, and anticoagulation should be prolonged accordingly. Meanwhile, surgical intervention should be performed as soon as possible to reduce the incidence of stent occlusion when stent stenosis occurs during follow-up.