Patients with moyamoya disease often have cogaitive impairment. The specific mechanisms are unclear. Surgical intervention relieving low perfusion state of cerebral blood flow may be the only effective way in the treatment of moyamoya disease, maintain or improve coaitive fimction at present; however the related surgical indications, timing of sury, postoperative hyperperfusion syndrome, as well as long-term efficacy and other issues must be resolved.