Epilepsy is a common condition with a prevalence of about 7 per 1,000 in the population; there are about 9 million or more people with epilepsy in China, seen in all age groups. Theoretically, epilepsy has a cause, but some causes are still being explored, limited by the limitations in the understanding of epilepsy. The etiology of epilepsy is complex, and many central nervous system or systemic disorders can cause epilepsy. Such that a definite cause can be found are called secondary epilepsy or symptomatic epilepsy. Although the cause cannot be found by applying various methods, this type of epilepsy is medically known as primary epilepsy (idiopathic). Those presumed to be symptomatic but for which the cause is not yet clear are called cryptogenic epilepsy. Alzheimer’s disease, etc.; 9, drugs and poisons; 10, other: systemic lupus erythematosus, hypoglycemia, diabetes mellitus, etc. In conclusion, there are many causes of epilepsy, and their etiology should be determined by the epileptologist based on history, signs and combined with the necessary ancillary tests. Epilepsy in infancy is mainly related to birth injury, hemorrhage, metabolic disorders or genetic factors; epilepsy in childhood and adolescence is mainly related to inflammation, parasites, traumatic brain injury and cortical developmental disorders; traumatic brain injury is also a common cause of epilepsy in adults, and generally speaking, the more severe the traumatic brain injury, the greater the likelihood of epilepsy; brain tumors can also cause seizures, but mainly in adults; stroke is a more common cause of epilepsy in the elderly. Some seizures can occur during the acute phase of a stroke, while others occur after the acute phase.