The banded mercury tabletop sphygmomanometer measures blood pressure most accurately, while the electronic sphygmomanometers currently in use are prone to certain deviations. When measuring blood pressure in general, it is important to master the correct measurement method, because the blood pressure of the extremities is different. The blood pressure of the upper extremities is lower than that of the lower extremities, and the heart is located on the left side and is easily affected by the blood supply to the heart muscle, so the blood pressure measurement is based on the blood pressure of the upper extremities on the right side. And monitor the same time period of two blood pressure, both higher than 140/90mmhg to be able to diagnose hypertension. It is best not to space clothes when measuring blood pressure, especially loose clothing such as sweaters, which can easily make the blood pressure measurement high, and not to put the stethoscope head inside the harness.