The mercury column sphygmomanometer involves listening to the sound of the pulse beat to determine high as well as low pressure. Blood pressure is measured with the patient in a seated position, resting quietly for 10 minutes or more. During the measurement, the pressure of the mercury column is pumped to more than 20 mmHg above the target blood pressure, after which it is slowly deflated and the first pulse is heard as high pressure, after which it is gradually deflated and the last pulse is heard as low pressure. At present, the mercury column sphygmomanometer has been gradually eliminated, the application of electronic sphygmomanometer is more and more widely used and more and more mature, after testing the electronic sphygmomanometer and the mercury column sphygmomanometer is not much different, it is recommended that patients without basic medical knowledge can buy electronic sphygmomanometer for blood pressure monitoring.