Clinically and in life, we often see patients with sudden cardiac death, a condition that can lead to death if not resuscitated in time. Sudden cardiac death is faced with cardiopulmonary resuscitation once it occurs. If the sudden death occurs outside the hospital, if the patient falls to the ground and is judged to be a sudden cardiac death, the most effective first aid method at this time is CPR. On-site hands-only CPR is divided into three main steps: opening the airway, artificial respiration and chest compressions, generally known as the ABC steps. First determine consciousness and open the airway. The rescuer is located on the right side of the patient’s head and chest, takes a squatting or kneeling position, places the patient in a prone position flat on the ground, removes foreign objects from the mouth and nose, and makes the patient tilt his head and lift his chin. Then perform mouth-to-mouth respiration and chest cardiac compressions to establish artificial circulation. The frequency of chest compressions is 80-100 times per minute, and the ratio of compressions to artificial respiration is 15:2 for single resuscitation and 15:1 for double resuscitation. If sudden cardiac death occurs in a hospital, there must be professional medical personnel to perform resuscitation measures. If the patient is not in ventricular fibrillation causing cardiac arrest, cardiopulmonary resuscitation measures such as chest cardiac compressions, mouth-to-mouth artificial respiration, pressurized oxygen administration, mechanical ventilation after tracheal intubation, and cardiac monitoring should be performed immediately until the heartbeat and autonomic breathing are restored. If the patient is in cardiac arrest due to ventricular fibrillation, precordial percussions are given, and an asynchronous electric shock with a defibrillator is prepared to restore the heart rhythm. After establishing intravenous access, resuscitation medications are administered as prescribed. In the event of sudden cardiac death, time is of the essence and the patient’s hope of survival decreases every 1 minute. If the delay is too long, due to brain damage caused by cerebral ischemia, even if the life is saved, it may be called “vegetative”.