〔Abstract〕 Objective To investigate the influencing factors of iliac branch occlusion in patients with abdominal aortic aneurysm after endovascular aneurysm repair (EVAR). Methods The clinical data of 60 patients with abdominal aortic aneurysm who had iliac branch occlusion after 3 months of follow-up after EVAR from January 2020 to January 2021 in the First Affiliated Hospital of Henan University of Science and Technology were collected and included in the occurrence group, the clinical data of 60 patients with abdominal aortic aneurysm who did not have iliac branch occlusion after 3 months of follow-up after EVAR during the same period were collected and included in the non-occurrence group. The clinical data of patients were reviewed, and the factors that may affect the iliac branch occlusion were counted. Logistic regression analysis was used to summarize the influencing factors of iliac branch occlusion in patients with abdominal aortic aneurysm after EVAR. Results The patients in the occurrence group were compared with the patients in the non-occurrence group in terms of poor preoperative tumor neck conditions, twisted iliac artery approach, preoperative iliac artery stenosis ≥ 50 %, and iliac branch stent distal diameter amplification rate > 15 %, the difference was statistically significant (P < 0.05). There was no statistical significant difference in age, sex, operation time and intraoperative blood loss between the two groups (P > 0.05). Multivariate logistic regression analysis showed that poor preoperative aneurysm neck conditions, large distortion of the iliac artery approach, preoperative iliac artery stenosis ≥ 50 %, and iliac branch stent distal diameter enlargement rate > 15 % were risk factors for iliac branch occlusion after EVAR in patients with abdominal aortic aneurysm (OR > 1, P < 0.05). Conclusion The occurrence of iliac branch occlusion in patients with abdominal aortic aneurysm after EVAR is affected by factors such as poor preoperative neck condition, large distortion of iliac artery approach, preoperative iliac artery stenosis ≥ 50 %, and distal diameter magnification of iliac branch stent > 15 %. Clinically, targeted prevention and treatment programs can be proposed to reduce the incidence of iliac branch occlusion after EVAR in patients with abdominal aortic aneurysm.