The primary, secondary and tertiary prevention of cerebrovascular disease are like three lines of defense, among which the primary prevention has the greatest effect and is the most important, because the target of its prevention is the total population of the society or the high-risk group of them. With a population of 1.3 billion people, the number of high-risk groups in China is quite large, so the benefits of prevention are quite obvious. Moreover, primary prevention focuses on health education and behavioral interventions, and the investment is minimal, compared to the increasingly expensive medical costs. Primary prevention is prevention at the source, mainly to control the causes and risk factors of stroke before the onset of stroke, also known as radical prevention or etiology prevention. 1, prevention and control of hypertension: active control of hypertension can reduce the incidence of stroke and mortality by more than 40%, therefore, control of hypertension is the most important primary prevention of stroke. 2, prevention of cardiogenic stroke ①Patients with rheumatic heart valve disease and myocardial infarction, who are at high risk for cardiogenic cerebral infarction, should take long-term oral anticoagulants or antiplatelet aggregation drugs to prevent stroke, and when surgery is indicated, surgery should be performed as early as possible. ②Atrial fibrillation: non-rheumatic atrial fibrillation is an important cause of cardiogenic cerebral infarction, mostly seen in the elderly. As the proportion of elderly population increases, the number of cerebral embolism caused by atrial fibrillation also increases, mainly embolizing the middle cerebral artery trunk and causing large infarcts in the cerebral hemisphere. Therefore, chronic atrial fibrillation patients over 75 years of age should take long-term oral Huafarine if they have decreased left ventricular function or intracardiac appendage thrombosis, or have previous thromboembolic diseases. chronic atrial fibrillation patients under 75 years of age without the above risk factors should take oral aspirin to prevent the occurrence of cerebral embolism. 3, prevention and control of diabetes mellitus can lead to microangiopathy and promote atherosclerosis, which is a risk factor for the development of stroke. 4, prevention and control of hyperlipidemia hyperlipidemia accelerates atherosclerosis. 5. Eat properly, reduce sodium intake, exercise properly, control weight, and stop smoking and drinking. Secondary prevention, also known as “three early prevention”, namely early detection, early diagnosis and early treatment. Secondary prevention is the main measure to prevent or slow down the development of the disease during the onset of the disease. It is mainly aimed at those who have had a transient ischemic attack or have recovered from a mild stroke within a short period of time (3 weeks) to prevent a complete stroke. To control the disease and prevent the occurrence of complications. Tertiary prevention is mainly for active treatment after the onset of the disease to prevent deterioration and preventive measures to reduce complications and prevent in recurrence.