The best time for trauma first aid is: 1. to carry out effective cardiopulmonary cerebral resuscitation within 4 minutes after the injury; 2. to complete the treatment of controlling bleeding, relieving asphyxia and keeping the airway open within 10 minutes of first aid; 3. to effectively intervene and control shock within 30 minutes of shock; 4. to carry out definitive life-saving surgery within the golden hour to rescue bleeding from internal organ injuries in the chest, abdomen and pelvis, serious cranio-cerebral injuries and other life-threatening conditions, so as to obtain a high survival rate of first aid.