Abstract: Objective: The underlying mechanisms of basilar artery (BA) plaque distribution remain unclear, thereby garnering considerable research attention. This study investigates the characteristics of atherosclerotic plaques in the BA with moderate to severe stenosis using 3.0T high-resolution magnetic resonance imaging (HR-MRI) and examines their clinical significance. Methods: Imaging and clinical data of 98 patients with atherosclerotic moderate to severe BA stenosis (≥50%) presented with ischemic stroke symptoms in the BA territory (treated at Beijing Geriatric Hospital from December 2021 to December 2024) were retrospectively analyzed. Based on the presence of acute infarcts on diffusion-weighted imaging, the patients were classified into an acute cerebral infarction (ACI) group and a transient ischemic attack (TIA) group. All patients underwent HR-MRI within two weeks to characterize plaque geometry (location, length, and distribution) and identify plaque features, namely rupture of fibrous cap (RFC) and intraplaque hemorrhage (IPH). Associations between these features and acute infarction were analyzed. Results: A total of 98 patients were included—46 and 52 in the ACI and TIA groups, respectively. The mean plaque length was (12.23±5.34) mm in the ACI group and (11.21±6.36) mm in the TIA group, with no significant difference. Regarding plaque distribution, no statistically significant differences were observed between the two groups in the proportions of plaques located distal or proximal to the anterior inferior cerebellar artery, or on the dorsal wall. However, significant differences were observed in plaque RFC, IPH, as well as distribution at the junctional segment, ventral wall, and lateral walls (all P < 0.05).Plaques in the ACI group formed predominantly on the lateral wall (43.75%) and dorsal wall (34.37%), compared with only 21.88% on the ventral wall. Compared with the ACI group, plaques in the TIA group showed a greater predilection for the ventral wall. Conclusion: Plaques located on the lateral and dorsal walls are more likely to cause acute infarction than those on the ventral wall. Additionally, plaque location at the BA junctional segment, presence of RFC, and presence of IPH are risk factors for acute infarction. HR-MRI not only provides a noninvasive method for predicting acute cerebral infarction but also offers critical guidance for subsequent endovascular stenting.