The peak of human blood pressure has two time periods, respectively 6:00-10:00 in the morning and 16:00-20:00 in the afternoon, and generally the highest blood pressure in the afternoon throughout the day. Most people’s blood pressure fluctuation pattern for 1 day 6:00-10:00 and 16:00-20:00 two times the highest blood pressure, night or early morning blood pressure is the lowest, so patients should take antihypertensive drugs in the morning after waking up, afternoon attention to monitor the blood pressure is stable state. If you need to further clarify the time point of the patient’s highest blood pressure, you can conduct ambulatory blood pressure monitoring to assess the patient’s overall blood pressure fluctuation pattern of 24 hours, especially in hypertensive patients, has broken the regular blood pressure fluctuation pattern change trend, “double peak a valley” pattern, hypertensive patients may be mainly high blood pressure at night, or high blood pressure in the early morning . Ambulatory blood pressure monitoring can detect hidden hypertension as well as the cause of intractable hypertension, and assess the variability of blood pressure elevation, circadian rhythm, and the effect of medication treatment.