The EEG is a graph obtained by magnifying the spontaneous bioelectricity of the brain from the scalp with a sophisticated electronic instrument. It is used to determine the cause and type of epilepsy, to select drugs, to adjust drugs, to locate epileptic foci, to assess the need for surgery, and to find the cause of cognitive impairment. In the diagnosis of epilepsy, the EEG is known as the “gold standard”. Currently, conventional EEG, long-range EEG, dynamic EEG, video long-range EEG, and stereotactic EEG are used in clinical practice. Conventional EEG Conventional EEG usually takes about 20-40 minutes to record, but epileptiform discharges are very random, so it is often difficult to capture epileptiform discharges, and the usage rate is gradually decreasing. Long-range EEG The long-range EEG is characterized by a long recording time, which can help to detect abnormal brain waves in epileptic patients and reduce the possibility of missed diagnosis. However, it should not be overlooked that long-range EEG is more susceptible to interference, sometimes the patient’s activity cannot be videotaped, and sometimes the relationship between seizures and EEG is not well determined. Dynamic EEG Dynamic EEG is also called portable EEG. Dynamic EEG can usually be recorded continuously for about 24 hours, so it is called 24-hour EEG monitoring, but since there is no video equipment, it is mainly used for patients with epilepsy whose seizures are difficult to capture on short-range EEG recordings, who have fewer seizures and whose seizures are already under control. Video long-range EEG Video long-range EEG belongs to scalp electrodes, which adds synchronized video equipment to the basic EEG equipment, and is able to film the patient’s clinical situation while detecting intracranial discharges, and is mostly suitable for positioning examination before surgery for epilepsy patients. Stereo – electroencephalography (SEEG) is a new technique for localizing epileptic foci that has emerged internationally in recent years. Stereo – electroencephalography introduces the localization method from 2D to 3D level, providing a comprehensive three-dimensional coverage of the brain, thus achieving accurate localization of the lesion and improving the treatment effect. Stereotactic electrodes can be implanted using a minimally invasive method in the deep frontal lobe, medial side of the brain, cingulate gyrus, medial temporal lobe and other areas that cannot be reached by conventional cortical electrodes. The path of electrodes is set before surgery to precisely and effectively ensure the therapeutic effect, thus avoiding intracranial arteries and veins, maximizing the protection of brain function and greatly reducing the risk of surgery.