The main reasons for waking up in the middle of the night with headache include: cluster headache, subarachnoid hemorrhage and cerebral infarction. 1. Cluster headache: it is a kind of vascular headache, mostly occurring in 20-40 years old young adults, mostly at night, when the disease attacks the headache is usually severe and intolerable, resulting in headache pain in the middle of the night to wake up. It is usually accompanied by conjunctival congestion, pupil constriction, tearing, runny eyes and other manifestations. 2. Subarachnoid hemorrhage: Suddenly, severe headache occurs at night, sometimes with bursting pain. In severe cases, nausea, vomiting and other intracranial pressure increase may occur. 3. Cerebral infarction: it can be related to atherosclerosis caused by hyperlipidemia, age and other factors. As the blood vessels in the patient’s brain are obstructed by blood clots, resulting in ischemia and lack of oxygen in the brain, which may lead to sudden and severe headache in the middle of the night, and most of them are accompanied by hemiplegia, nausea, vomiting and other symptoms. If you wake up in the middle of the night with a headache, you should pay attention to it and go to the hospital as soon as possible to get a clear diagnosis and symptomatic treatment.