Abstract: Objective: To explore the etiology,clinical presentation,pathogenesis and imaging features in top of the basilar artery syndrome(TOBS).Methods: The clinical and imaging data of 12 cases with TOBS were reviewed and analyzed.Results: Unconsciousness(75.0%),disturbance of eyeballs(66.7%),dyskinesia(58.3%),vertigo(58.3%),and abnormality of pupils (50.0%) were the most common symptoms and signs.The common etiology was embolism and cerebral thrombosis;the high risk factors were hypertension(75.0%),diabetes mellitus (33.3%),hyperlipemia(25.0%) and etc.;the imaging features in TOBS included infarction in midbrain and thalami(75.0%)and/or other sites,such as cerebellum(33.3%),occipital(41.7%),temporal lobes (41.7%)and so on.Conclusions: Complicated clinical manifestation and imaging features are often seen in TOBS.The etiology and high risk factors are similar to the cerebral stroke.Head MRI will help to accurate diagnosis.