The principle of epileptic seizures is complex, simply put, it is the abnormal discharge of neurons in the brain, which is manifested as “abnormal waves” on the EEG. It is difficult to diagnose the cause and “epileptogenic focus” of epilepsy, and it requires repeated and even induced seizures to be diagnosed after EEG examination. Traditionally, the diagnosis of epileptic seizures can be made only by asking medical history, but with the rapid development of electronic technology, EEG diagnostic technology has now been greatly improved and is one of the important clinical examination means to confirm the diagnosis of epilepsy, so epileptic patients should not ignore EEG examination. It highlights the advantages in the following aspects: to assist in diagnosis: it is easier to do EEG diagnosis in patients with typical symptoms, and it takes several times or 24-hour dynamic EEG system examination to diagnose in patients with atypical symptoms. Also, an EEG can rule out seizure-like disorders such as syncope and childhood migraine. Guidance on medication: When the epileptic patient is seizure-free after 2-5 years of standardized medication, medication reduction can be considered, but the dosage can be gradually reduced only after the EEG has not shown any “abnormal waves” for several times before reduction. The key to surgical treatment can be the preoperative localization of epileptogenic foci by advanced EEG.