Objective To investigate the efficacy and safety of endovascular recanalization 6-24 h after onset in patients with acute basilar artery occlusion,and explore the related factors for their prognoses.Methods Clinical data of 37 patients with acute basilar artery occlusion,received endovascular recanalization in our hospital from January 2016 to July 2019,were retrospectively collected;23 patients were into group of onset-to-puncture time (OPT)＞6 h (6-24 h),and 14 patients were into group of OPT ≤ 6 h (0-6 h).Statistical methods were used to compare the postoperative symptomatic intracranial hemorrhage rate,good prognosis rate (modified Rankin scale [mRS] scores ≤ 3) and mortality 3 months after onset between the two groups;clinical data between the subgroups with good and poor prognoses in patients of group of OPT＞6 h were compared.Results The postoperative symptomatic intracranial hemorrhage rate,and good prognosis rate and mortality of patients from group of OPT＞6 h were 30.4％,47.8％ and 43.5％,respectively;and there were no statistically significant differences as compared with those in patients from group of OPT≤6 h (35.7％,35.7％,and 42.9％,P＞0.05).Scores of scales based on preoperative CTA images (posterior circulation-Alberta stroke program early CT scale [pc-ASPECTS],scale of posterior circulation on CTA [pc-CTA],and scale of basilar artery on CTA [BATMAN]) showed significant differences between the good prognosis subgroup and poor prognosis subgroup in patients fiom group of OPT＞6 h (P＜0.05).Conclusion Endovascular recanalization 6-24 h after onset is effective in patients with acute basilar artery occlusion,and the safety does not obviously decrease;scores of pc-ASPECTS,pc-CTA and BATMAN may be related to the clinical prognoses.