In clinical practice, the primary purpose of first aid is to maintain the patient’s vital signs stable and save the patient’s life, and the secondary purpose is to reduce or avoid the further progress of the relevant condition, so as to obtain the corresponding rescue means and time for the subsequent treatment. For example, for patients in cardiac arrest, firstly, cardiopulmonary resuscitation should be adopted to save and resuscitate the patient’s life. Secondly, the patient’s respiratory and circulatory functions should be maintained relatively stable to buy time for the later relevant causal treatment. At the same time, the patient should be given appropriate psychological guidance to avoid aggravating the condition due to emotional stress, and the patient should be given symptomatic support treatment. Other first aid includes first aid for cardiovascular and cerebrovascular diseases, first aid for burns, and first aid for trauma in the field.