Ambulatory blood pressure is the measurement of a person’s blood pressure values at certain intervals over a 24-hour period, day and night. Ambulatory blood pressure monitoring is not only used for diagnostic assessment of hypertension, but also for diagnosing white coat hypertension, detecting hidden hypertension, examining the causes of intractable hypertension, and assessing the degree of blood pressure elevation, short term variability and circadian rhythm, etc. For patients with hypertension, frequent measurement of ambulatory blood pressure is of great importance to the management of hypertension in patients. The ambulatory blood pressure recorder consists of a transducer, a micro recorder, and a recovery system. It can inflate the cuff at regular intervals, measure brachial artery blood pressure, and store data automatically. Up to 200+ blood pressure values can be stored in a day, and then the blood pressure values are analyzed and printed out in the full recovery system. Ambulatory blood pressure has the following advantages compared with occasional blood pressure: 1, in addition to the occasional blood pressure of chance, to avoid the emotions, exercise, eating, smoking, drinking and other factors affect blood pressure, more objective and realistic reflection of blood pressure. 2, ambulatory blood pressure can be known more blood pressure data, can actually reflect the blood pressure in the whole day change pattern. 3, for early asymptomatic light hypertension or critical hypertension patients, improve the detection rate and can be timely treatment. 4, ambulatory blood pressure can guide drug treatment. In many cases, it can be used to determine the effect of drug therapy, help to select drugs, adjust the dose and time of administration. 5, to determine whether hypertensive patients have target organ (vulnerable to hypertension damage organs) damage. Hypertensive patients with cardiac hypertrophy, fundus dynamic vasculopathy or renal function changes have a smaller difference between day and night. 6. Predicting the time of day when cardiovascular disease suddenly strikes. Cardiovascular disease is most likely to occur in the early morning when blood pressure rises suddenly. Ideal blood pressure control should include the entire 24-hour blood pressure, ambulatory blood pressure monitoring, because there is no “white coat hypertension” and placebo response, can correctly evaluate the treatment process at rest and activity and circadian rhythm and the duration of drug action, according to the time of the peak and trough of blood pressure, the choice of action It is possible to select antihypertensive drugs with different duration of action according to the time of peak and trough of blood pressure, to control blood pressure more effectively and to reduce adverse drug reactions. Many hemodynamic indicators including systolic blood pressure, diastolic blood pressure and heart rate, as well as the occurrence of cardiovascular events such as myocardial infarction, sudden cardiac death and stroke have obvious and similar diurnal patterns of variation, such as during the early morning when many of the former indicators begin to rise rapidly near their peak, and the latter has the highest rate of unintended events throughout the day, between which seems to be due to neurohumoral factors or blood coagulation system This requires that any antihypertensive drug used clinically should provide antihypertensive protection throughout the day; especially in the early morning, rather than lowering the episodic blood pressure at a given moment or the average ambulatory blood pressure value over a 24-hour period. In conclusion, the application of ambulatory blood pressure measurement methods has led to increased awareness of the variability of blood pressure, the effect of environmental stimuli on blood pressure, the distinction between high-risk and low-risk patients in populations with similar blood pressure values measured in clinics, and the observation of the effects of antihypertensive therapy, providing new avenues for clinical and epidemiological studies of hypertension. Therefore, the 2010 guidelines for the prevention and treatment of hypertension recommend the importance of ambulatory blood pressure monitoring, which can better and more realistically evaluate the level of patients’ blood pressure and better guide physicians in formulating reasonable pharmacological treatment measures.