Objective: To explore the roles of long-term intracranial EEG recording in patients with intractable epilepsy for localizing epileptogenic zone. Methods: Fourteen refractory epilepsy patients, whose seizure onsets were unable to be localized with CT/MRI imaging and scalp EEG recording, received intracranial EEG monitoring with depth and/or subdural strip electrodes. Results: Seizure onset zone was detected by the ictal intracranial EEG recordings at the initial stage of seizures(n = 47). Based on the data of pathological examination, postoperative EEG recordings and clinical follow-up, we found that(1) Epileptogenic zone were accurately localized in eleven patients (78.5%). They were seizure free or had rare seizures after surgery. (2) Seizure attack improved in two patients. (3) Seizure attack did not show any improvement in one patient. For all patients, no significant complications were observed. Conclusions: The implantation of intracranial electrodes in selected patients is safe and effective. The position and extent of the initial ictal EEG discharges are reliable information for localizing epileptogenic zone.