Stroke refers to cerebrovascular accidents, including ischemic stroke (i.e., cerebral infarction) and hemorrhagic stroke (i.e., cerebral hemorrhage), both of which have a variety of causes. The causes of ischemic stroke mainly include: (1) atherosclerosis, the plaque formed by atherosclerosis is the main factor causing the narrowing of blood vessels, and the huge plaque can directly cause serious narrowing of arteries and then lead to occlusion, the narrowing of blood vessels will lead to a decrease in blood flow, resulting in decreased perfusion and slowed blood flow in distal arteries, which will further form thrombus and cerebral infarction; there is also a part of unstable The plaque will lead to the destruction of the intima of the blood vessel, and then form platelet aggregation locally to form thrombus, or cause the rupture of the lipid inner core of the plaque, and these thrombi and dislodged plaques are carried away by the blood flow and blocked in the distal vessels, and then embolism is formed. (2) Atrial fibrillation can cause the embolus to fall off, and the dislodged embolus forms with the blood flow forward, blocking small blood vessels, and if blocked in the cerebral artery, it forms a cerebral infarction, and this type of cerebral infarction is called cardiogenic embolism. (3) The blood itself can also lead to the formation of thrombus due to a variety of factors such as autoimmunity or abnormal coagulation mechanism, forming a stroke. In addition, there are other rare factors and unexplained causes of ischemic stroke. The causes of hemorrhagic stroke include: (1) hypertension combined with fine arteriosclerosis, long-term hypertension makes the wall of fine arteries less elastic, and blood vessels are prone to rupture and bleeding when blood pressure rises suddenly. (2) Other causes are less common than hypertension, including cerebral arteriovenous malformations, cerebral amyloid angiopathy, anomalous vascular network disease at the base of the brain, cerebral arteritis, hematologic disease, thrombolytic or anticoagulant therapy, etc. In summary, the causes of stroke are complex; the most common cause of ischemic stroke is atherosclerosis, and the most common cause of hemorrhagic stroke is hypertension. In the treatment of stroke, the first step is to distinguish the cause of the disease in order to provide targeted treatment.