Objective: To analyze the risk factors for iliac limb occlusion after endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm. Methods: The clinical data of patients with abdominal aortic aneurysm undergoing EVAR between January 2011 and December 2015 were collected. By a 1:3 matched case-control design, for each case with iliac limb occlusion, 3 patients of the same sex, age (within 3 year), and receiving stent of the same type and same manufacturer were randomly selected as control. The risk factors for iliac limb occlusion after EVAR were determined by univariate and multivariate Logistic regression analysis. Results: A total of 495 patients with abdominal aortic aneurysm underwent EVAR, among them, 11 cases (2.2%) developed iliac limb occlusion, and the average time to onset was 2-20 weeks after surgery. Univariate analysis showed that preoperative iliac artery angulation/tortuosity≥60° (P=0.001), preoperative iliac artery stenosis≥50% (P=0.002) and graft oversizing of the distal end of the iliac limb>15% (P=0.004) were significantly associated with post-EVAR iliac limb occlusion. Multivariate Logistic regression analysis revealed that all the above variables were independent risk factors for post-EVAR iliac limb occlusion (all P<0.05). Conclusion: Rigorous preoperative surgical plan based on the anatomic features of the iliac artery and selection of appropriate stent size are critical for reducing postoperative iliac limb occlusion. The high-risk patients should be identified and preventive measures of the controllable factors should be taken to avoid or reduce the occurrence of postoperative iliac limb occlusion.