Objective To explore the intraoperative oculomotor nerve monitoring during skull base tumor surgery for injury avoidance.Methods The study was conducted from January 2006 to January 2012.Monitoring group:35 skull base tumor operations were monitored by neurophysiology (22 males and 13 females).Control group:26 skull base tumor operations without intraoperative monitoring were treated with microsurgery alone (16 males and 10 females).The prognoses of different groups were evaluated.Results Monitoring group:2 cases had injury of oculomotor nerve.One of them suffered mild diplopia and recovered one months later.Another one had blepharoptosis and mydriasis,reaction to light was absent and recovered six months later.Control group:6 cases had injury of oculomotor nerve.Five of 6 cases recovered six months later.And one showed no recovery after a 1-year follow-up.Conclusion Intraoperative monitoring of oculomotor is essential for the protection of oculomotor nerve during skull base tumor surgery.