The steps of cardiopulmonary resuscitation are to first perform artificial chest compressions, then open the airway, and finally perform artificial respiration, cardiopulmonary resuscitation needs to pay attention to the following points: 1, the frequency of compressions: the site of chest compressions is the lower part of the sternum at the mid-point of the double nipple connection, and the frequency of compressions is 100-120 times/minute; 2, the amplitude of compressions: for adults to perform chest compressions, the amplitude of compressions should not be less than 5cm; 3, Artificial respiration time: open the airway should be carried out after 30 times of cardiac compression, after opening the airway, two artificial respiration should be carried out, and the duration of each time should be more than one second, to ensure enough tidal volume, so that the chest is undulating; 4, the ratio of compression and ventilation: whether it is a single person or a pair of people for cardiopulmonary resuscitation, the ratio of compression and ventilation is 30:2, and it should be carried out in an alternating manner. If CPR is performed on children or infants, the ratio of compressions and ventilation should be 15:2.