Normal blood pressure should be between 140/90mmHg-90/60mmHg, which is the normal blood pressure. The so-called pressure difference is the difference between systolic and diastolic blood pressure, which is usually above 20 mmHg in normal people. Individuals may have a small or large differential pressure, which should be considered separately. If a hypotensive patient has a blood pressure below 90/60 mmHg, the differential is small when the systolic pressure is low, i.e., a person with a small differential pressure may have hypotension. Or some patients are caused by high diastolic blood pressure, which is actually a kind of hypertension, resulting in a small pressure difference, and a large pressure difference also has the possibility of hypertension. Therefore blood pressure is not looking at the differential pressure, but at the presence or absence of hypertension. In short, the pulse pressure difference should generally be above 20 mmHg, and the main thing should be to determine whether the patient has hypertension, and patients with hypertension, regardless of the pressure difference, should be seen promptly.