There are currently two main methods of blood pressure measurement, namely invasive direct measurement and indirect measurement. The invasive direct measurement method is a way for the doctor to measure the pressure inside the blood vessel directly through the relevant device; the indirect measurement method is to measure the pressure in the brachial artery with the help of an electronic sphygmomanometer or mercury column sphygmomanometer to reflect the blood pressure level of the human body. The correct posture and wrong posture of blood pressure measurement The body should be straight and relaxed when measuring blood pressure, and the center of the arm band should be at the same height as the heart, and the ideal height difference between the table and the chair is 25-30 cm. If the measurement is taken in a forward leaning posture, the center of the arm band is lower than the position of the heart, or the arm band is too loose during the measurement or the measurement process is talking or moving, it can affect the accuracy of the measurement. Second, how to self-measure blood pressure in patients with hypertension Regular monitoring of blood pressure in patients with hypertension is beneficial for assessing the condition. For ease of operation and accuracy, home monitoring of blood pressure is best to use the upper arm electronic sphygmomanometer. The operation steps are as follows: 1, the arm band on the upper arm to be measured, and make the arm band nozzle pointing to the small arm; 2, ensure that the lower edge of the arm band at 2-3cm from the elbow joint, and make the nozzle is located in the inner arm; 3, the body is straight, keep the center of the arm band and the heart is at the same level; 4, the lower arm flat, palm facing up, click to start. In order to ensure the accuracy of blood pressure measurement, the following matters should be noted when measuring blood pressure: 1, when measuring blood pressure should be careful to measure the same side of the arm at the same time every day; 2, before measurement should sit quietly for 5 minutes to maintain a relaxed mood; 3, before measurement should not drink coffee, strong tea, while urinating and defecating; 4, multiple measurements to obtain the average; 5, to ensure that the measurement environment is quiet and comfortable; 6, the elderly 6, the elderly and diabetic patients are prone to postural hypotension, it is recommended to measure the blood pressure in the lying or standing position.