Ambulatory blood pressure monitoring is a portable blood pressure monitoring method that uses indirect noninvasive measurements for 24 consecutive hours and tracks and records blood pressure at set time intervals. (1) It can provide multiple blood pressure measurements for 24 hours or longer, which has better repeatability and thus can detect patients with elevated blood pressure that is not easily detected by incidental blood pressure measurements, especially for those with elevated blood pressure at night, and can clearly diagnose hypertension; (2) Ambulatory blood pressure monitoring is less influenced by psychological behavior and placebo, which helps to exclude “white coat hypertension”; (3) Ambulatory blood pressure monitoring is less influenced by psychological behavior and placebo. (2) ambulatory blood pressure monitoring is less influenced by psychological behavior and placebo, which can help to exclude “white coat hypertension”; (3) the reflected blood pressure level and diurnal trend changes have a good correlation with the degree of target organ damage of the heart, brain and kidney, which can evaluate the prognosis of hypertensive patients. Studies have proved that patients with high mean 24-hour blood pressure values, large standard deviation and disappearance of circadian rhythm of blood pressure have a high possibility of serious target organ damage and a poorer prognosis; (4) It can provide information that cannot be obtained by conventional blood pressure measurement methods such as trough-to-peak ratio, and is a valuable indicator for evaluating the antihypertensive effect and maintenance time of anti-hypertensive drugs to guide clinical treatment; (5) Other: simultaneous DCG and ABP can observe the causal and chronological relationship between coronary artery disease, angina pectoris, arrhythmia and blood pressure increase or decrease, as well as the relationship between hypertension and HRV changes, changes in vegetative tone, etc., which is beneficial to speculate the prognosis and formulate reasonable treatment plans. Indications: (1) Those who have symptoms that may be caused by hypertension such as dizziness and headache and need differential diagnosis; (2) Those who have occasional elevated blood pressure and are suspected of having hypertension and need a clear diagnosis; (3) Those who have untreated hypertension, or are under treatment, or have poor treatment results, to observe the efficacy and guide treatment; (4) Those who have unstable blood pressure; (5) Those who have recalcitrant hypertension and primary hypertension; (6) Those with low risk factors (6) Patients with “office-based hypertension” white coat effect. Before monitoring, the nurse should fully understand the patient’s condition, whether he/she has taken antihypertensive drugs and when he/she stopped taking antihypertensive drugs, whether he/she has blood coagulation disorder and receives anticoagulation therapy, etc., assess the patient’s arm circumference, select the appropriate cuff, and decide whether to apply ABPM according to the clinical evaluation, and do a good job of explaining to the patient, relieving the patient’s nervousness and obtaining the patient’s cooperation, so as to facilitate the clinical treatment and care. This will facilitate the clinical treatment and care. 2 Strict operating procedures for monitoring First, check that the battery in the monitor is above 2.8 V, clear the original data in the monitor, create a new patient case on the ambulatory blood pressure analyzer software, and set the time to measure blood pressure according to the patient’s condition. When fitting the monitor to the patient, first measure the blood pressure in both upper arms, if the systolic blood pressure difference.