Hypoglycemic syndrome is a group of syndromes caused by various causes. Blood glucose concentration is often lower than 3.36mmol/L (60mg/dl). Severe and long-term hypoglycemia can cause extensive neurological damage and complications. Functional hypoglycemia and hepatic hypoglycemia are common, followed by hypoglycemia caused by insulinoma and other endocrine diseases. This disease is often misdiagnosed as hysteria, epilepsy, mental illness, brain tumor and encephalitis. After proper treatment, the symptoms can improve rapidly. Early identification of this disease is very important, which can achieve the purpose of cure. Delayed diagnosis and treatment will cause permanent neuropathy and irreversible, with poor consequences.