A 28-year-old male was admitted to our hospital with the complaints of numbness of the left upper limb and gait disturbance. Neurological examination disclosed slight left dysmetria, truncal ataxia and sensory disturbance at the dermatome of C8 and Th1. CT and MRI scans showed a large mass lesion in the left posterior fossa, ventricular dilatation, cavum septi pellucidi and cavum Vergae, empty sella, cervical syringomyelia and left tonsilar herniation. The tumor which attached to cerebellar tentorium was totally removed and a histological diagnosis of meningothelial meningioma was made. Postoperative MRI scan demonstrated a disappearing of syringomyelia with the improved tonsillar herniation. Association of syringomyelia with brain tumor is relatively rare, so its pathogenesis was discussed.