The normal blood pressure range is the diastolic blood pressure range of 60-89 mmHg and the systolic blood pressure range of 90-139 mmHg for 3 repeated measurements on non-same day. Systolic blood pressure of 90 to 139 mmHg and diastolic blood pressure of 60 to 89 mmHg belong to the normal blood pressure range. A systolic blood pressure of 120 to 139 mmHg and/or a diastolic blood pressure of 80 to 89 mmHg is considered to be a high normal blood pressure, which falls within the normal blood pressure range, but has a higher likelihood of developing hypertension. Blood pressure fluctuates and has a circadian rhythm, and there may be some errors in occasional blood pressure measurements, therefore, blood pressure should be measured at least three times on non-same days to have clinical reference value. A systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg measured 3 times on non-same days is considered high blood pressure, while a systolic blood pressure ≤90 mmHg and a diastolic blood pressure ≤60 mmHg is considered low blood pressure. Pulse pressure is the difference between systolic and diastolic blood pressure, the normal value of pulse pressure should be 20-40mmHg, >60mmHg is increased pulse pressure, suggesting that there may be atherosclerosis and other conditions. It is recommended that people with abnormal blood pressure should retest their blood pressure on a day other than the same day, and those who still have abnormal blood pressure after retesting should consult a doctor for further examination and treatment as prescribed by the doctor.