The search for the cause of epilepsy is an important step in the diagnosis of epilepsy, which can be helpful in selecting treatment and determining prognosis. On the one hand, medical and family history can provide some help, such as family genetic background, history of previous cranial trauma or central nervous system infection; on the other hand, modern high-resolution imaging is also very suggestive of etiology and can detect structural abnormalities, such as cortical developmental malformations and the detection of neonatal masses. Neonatal and infancy: congenital and perinatal factors (hypoxia, asphyxia, cranial birth injury), inherited metabolic diseases, malformations due to abnormal cortical development, etc. Childhood and adolescence: idiopathic (genetically related), congenital and perinatal factors (hypoxia, asphyxia, cranial birth injury), central nervous system infections, abnormal brain development, etc. Adulthood: cranial trauma, brain tumor, CNS infectious factors, etc. Geriatric period: cerebrovascular accidents, brain tumors, metabolic diseases, degenerative diseases, etc.