For a long time, in clinical research and practice in the cardiovascular field, the main goal of antihypertensive therapy has been to bring blood pressure up to standard, and physicians have paid less attention to fluctuations in blood pressure. There is now more epidemiological evidence that blood pressure variability plays an important role in the development of target organ damage and vascular events. Blood pressure variability refers to the degree of fluctuation in blood pressure over a given period of time and is the most basic physiological characteristic of blood pressure. Depending on the length of the observation period, blood pressure variability is divided into short-time blood pressure variability and long-time blood pressure variability. Short-time blood pressure variability refers to blood pressure variability within 24 hours and is evaluated by ambulatory blood pressure measurements. Long-term blood pressure variability refers to blood pressure variability over a period of days or weeks. The exact mechanisms affecting blood pressure variability are not known, and among the many factors affecting blood pressure variability, pressure receptor sensitivity is the main determinant. The easiest way to detect blood pressure variability is to perform 24-hour ambulatory blood pressure monitoring, using blood pressure standard deviation and coefficient of variation as indicators of blood pressure variability. Early morning hypertension, white coat hypertension, and occult hypertension are all phenomena of blood pressure variability. The systolic and diastolic blood pressure of the vast majority of people show an obvious circadian rhythm, and the variability of blood pressure in the early morning is the most obvious. In the early morning, when the human body turns from sleep to wakefulness and begins to move, blood pressure rises rapidly from a relatively low level to a higher level, and in untreated hypertensive patients, the systolic blood pressure rises by an average of 14 mm Hg in the early morning hours, and can even rise by 80 mm Hg. This phenomenon of a sharp rise in blood pressure in the early morning is called This rapid rise in blood pressure early in the morning is called the “morning peak” and is the main expression of short term blood pressure variability. Studies have confirmed that the “morning blood pressure spike” is an independent risk factor for the occurrence of cardiovascular events. In 2006, a study published in the American Journal of Hypertension included 507 patients with untreated hypertension, divided into four groups based on the magnitude of systolic blood pressure rise at morning rise, with an average follow-up of 7 years. The results showed that the incidence of left ventricular hypertrophy and cardiovascular death was associated with early morning blood pressure levels. That is, patients with the greatest early morning blood pressure elevation had a higher incidence of cardiovascular events and mortality. White coat hypertension, which is defined as elevated office measured blood pressure levels and normal home self-measured or ambulatory blood pressure, was once thought to be non-dangerous but is now proven to be associated with target organ damage and is independent of mean blood pressure levels. Occult hypertension, which is defined as normal office blood pressure but elevated home self-measured or ambulatory blood pressure, is associated with the occurrence of vascular events. Results of a clinical neurology study reported in The Lancet in 2010 showed that people with normal average blood pressure but occasional elevated blood pressure had a higher risk of stroke than those with very high average blood pressure levels but consistently stable blood pressure levels. This suggests that the greater the variability in blood pressure, the greater the impact on vital organs. Recent studies have shown that interval systolic blood pressure variability is a stronger predictor of stroke, while interval systolic blood pressure variability predicts the risk of myocardial infarction, angina pectoris and heart failure, independent of mean systolic blood pressure. Therefore, high-quality antihypertensive therapy requires not only strong and long-lasting antihypertension, but also smooth antihypertension. While blood pressure levels are attained, the variability of blood pressure is taken into account, and the adverse effects of blood pressure fluctuations are fully considered. In patients with persistent blood pressure fluctuations, office blood pressure, home self-measurement blood pressure, and ambulatory blood pressure monitoring should be performed to understand the degree of blood pressure variability in order to guide the selection of antihypertensive drugs so that cardiovascular and cerebrovascular events can be minimized.