The quality of chest compressions in CPR determines the success rate of CPR. Before the chest compressions, the site of compressions should be clearly defined. According to the latest resuscitation guidelines, the site of compressions is the junction of the middle and lower 1/3 of the sternum, which can be chosen by non-medical people, i.e., the intersection of the line between the nipples on both sides and the anterior midline. The frequency of chest compressions is specified as 100-120 times/minute, and the depth of compressions is 5-6 cm. The hand should not leave the chest wall during compressions to maintain the regularity of compression frequency and rhythm. When two people perform CPR, the ratio of compressions to ventilation is 30:2, that is, when 30 chest compressions are done, two artificial respirations should be given in time.