The anatomy of the trunks and branches of anterior inferior cerebellar artery(AICA) was studied and its surgical importance especially in the operation for acoustic neuroma(AN), was discussed.15 fresh adult cadavers were perfused with ABS via internal carotid artery and vertebral artery and then dissected under operation microscope in detail. AICA was constantly present in all specimens. The incidence of labyrinthine artery(LA), recurrent perforating artery(RPA), subarcuate artery(SA),and cerebellar subarcuate artery (Cer.SA) was 100%,86.7%,80% and 16.7%, respectively. 97.1% of LA entering the internal auditory meatus (IAM) were located under the facial vestibulocochlear nerve complex, 56.7% of RPA passed between it ,and 75% of SA was located posteroinferiorly to it .60.7% of the loop of AICA was situated close to the IAM, and 53.6% of them lay between the Ⅶ and Ⅷ cranial nerves. These data may be helpful in microneurosurgical operation and radiography.