Abstract：Objective To explore the influencing factors of ineffective recanalization after endovascular treatment (EVT) within 24 hours after the onset of acute cerebral infarction with basilar artery occlusion in the elderly patients. Methods A total of 242 elderly patients with basilar artery occlusive acute cerebral infarction who received EVT treatment within 24 hours of onset in our hospital from June 2021 to June 2025 were retrospectively included. They were divided into the effective group and the ineffective group according to the recanalization effect in 3 months after treatment. By comparing the data of the two groups, univariate and multivariate analysis methods were used to analyze the independent influencing factors of ineffective recanalization after endovascular treatment within 24 hours of onset in elderly patients with acute basilar artery occlusive cerebral infarction. Results 242 patients were enrolled in this study. Three months after EVT treatment, 130 cases had effective recanalization and 112 cases had no recanalization. The recanalization failure rate was 46.28%. Univariate analysis showed that the National Institutes of Health Stroke Scale score on admission, bridging intravenous thrombolysis before treatment, arterial occlusive lesion grade, symptomatic intracranial hemorrhage at 24 hours postoperatively, and the neutrophil-to-lymphocyte ratio were all associated with ineffective recanalization after endovascular treatment (EVT) within 24 hours of onset in elderly patients with acute basilar artery occlusive cerebral infarction (P＜0.05). Logistic multivariate analysis demonstrated that the National Institutes of Health Stroke Scale score on admission, bridging intravenous thrombolysis before treatment, arterial occlusive lesion grade, symptomatic intracranial hemorrhage at 24 hours postoperatively, and the neutrophil-to-lymphocyte ratio on admission were all independent risk factors for ineffective recanalization after EVT within 24 hours of onset in elderly patients with acute basilar artery occlusive cerebral infarction (P＜0.05). Conclusion The occurrence of ineffective recanalization after EVT within 24 hours after the onset of acute cerebral infarction with basilar artery occlusion in the elderly is independently associated with the score of the National Institutes of Health Stroke Scale at admission, whether intravenous thrombolysis was bridged before treatment, the grade of arterial occlusive lesions, whether there was hemorrhage transformation after surgery, and the ratio of neutrophils to lymphocytes.