Grade 3 hypertension is systolic blood pressure ≥ 180 mmHg and/or diastolic blood pressure ≥ 110 mmHg. According to the classification and definition of blood pressure levels currently used in China, hypertension is classified as grade 1 (mild), grade 2 (moderate) and grade 3 (severe) according to blood pressure levels without the use of antihypertensive drugs. patients with grade 3 hypertension are vulnerable to acute complications of hypertension, such as hypertensive encephalopathy, cerebral hemorrhage, cerebral infarction , heart failure, acute coronary syndrome, aortic coarctation, etc. For grade 3 hypertension, immediate antihypertensive treatment is required to reduce the incidence of cardiovascular events by gradually bringing blood pressure up to standard according to individualized principles.