Objective: To observe and evaluate sevoflurane anesthesia for intracranial aneurysm clipping and effects of Sevoflurane on plasma concentration of S-100B and make a decision whether the sevoflurane was suitable for intracranial aneurysm clipping.Methods: Thirty-four patient of ASA Ⅱ-Ⅲ grade scheduled for selective cranial aneurysm clipping were randomly divided into sevoflurane group(n=17)and propofol group(n=17).Anesthesia was induced and maintained with sevoflurane or propofol respectively.The operating field condition,awake orientation and short memory capability were observed.Surgery time and aneasthesia time,and clinical signs and the neurologic or surgery complications were recorded.Plasma concentrations of S-100B was measured with radioimmunoassay at scheduled time respectively.Results: There was no significant difference in the age ,gender,weight,and aneurysm kind consistant,surgery time,aneasthesia time ,fluid component and content for the surgery,blood loss in the surgery field(P>0.05) between the two groups.No significant difference in the operating field condition,awake scale orientation and memory capability was found.As compared with the base line,the plasma concentration of S-100B increased in two groups.t(P<0.05).While there was no significant difference in the plasma concentration of S-100B between the two groups at the time after the operation or 48h after the event.Conclusions: Just like propofol,sevoflurane can be a suitable anesthesia for intracranial aneurysm clipping which will not lead to brain injury.