First, the examinee is asked to sit quietly for 5 min, then the examinee sits on a bench to expose one arm, so that the elbow joint and the heart, sphygmomanometer on the same plane. Again, the mercury tank switch is turned on and the cuff is wrapped around the upper arm, with the lower end of the cuff 2-3 cm away from the elbow fossa as appropriate. Turn off the balloon switch and start squeezing the balloon so that the brachial artery pulsation disappears and then rises by 20-30 mmHg, then start deflating slowly, when the first sound of brachial artery pulsation is heard the systolic pressure is recorded, continue deflating and when no brachial artery pulsation is heard the diastolic pressure is recorded. Finally, remove the cuff to drain the air and tilt the sphygmomanometer to close the mercury tank switch.