Abstract： Objective To study intraoperative epilepsy inducing test and its effect in the epileptogenic focus resection.Method The study included 118 patients with refractory epilepsy.During surgery,the patients were first woken up.With cortical and depth electrodes,the patient's spike wave,sharp wave or spike slow,sharp slow complex wave,etc.were monitored.The range of epileptogenic foci was marked with digital label.Under deep anesthesia,the foci was resected and the cortex was heat burned.The patients were woken up again,and hyperventilated,the carbon dioxide partial pressure (PCO2) kept at 20 ～ 25 mmHg for 5 minutes.The brain waves were measured again.After marking the spike and sharp waves,the anesthesia was deepened again,and resection and cortex heat burning were applied.Results (1) Of the 118 patients,except 3 children performed under light anesthesia because of noncooperation,115 patients all successfully underwent the surgery,going through consciousness recovery,hyperventilation inducing test after general anesthesia,without intraoperative seizures.(2)According to the results by arousal conditions,despite postoperative epileptic wave basically disappeared,the epileptic waves were still detected in 63 patients after hyperventilation inducing test.The epileptic wave disappeared after repeated operation and hyperventilation inducing test.(3) Postoperative follow - up showed no operative death,incomplete motor aphasia in 2 cases and recovered in 6 months.2 cases with incomplete paralysis recovered after 1 year.3 patients with glioblastoma died.5 patients were not traceable.110 patients were followed up for 3 -33 months (mean 18.5 months).According to Engel's postoperative evaluation,74 cases were grade Ⅰ,27 cases were grade Ⅱ,6 cases were grade Ⅲ,3 cases were grade Ⅳ.Conclusions Intraoperative epilepsy inducing test has very important significance in the epileptic focus resection and deserves to further exploration.