Electroencephalogram (EEG) is of great value for the diagnosis and differential diagnosis of epilepsy, and is an indispensable auxiliary examination for the diagnosis of epilepsy. However, about 5-20% of epileptic patients have normal EEG in the interictal period; in addition, due to the short time of ordinary EEG topography and routine EEG, epileptiform discharge waves cannot be captured. Therefore, the diagnosis of epilepsy cannot be ruled out clinically just because the EEG is normal, but the doctor must analyze it together with the medical history and clinical seizure manifestations in order to make a correct diagnosis.