Burns are the most common trauma in daily life and warfare, and can be classified as thermal, chemical, electrical and radiological burns according to their causes. On-site first aid is an important part of treatment, and the control of anti-shock and trauma infection is the key to successful resuscitation. Many people believe that they cannot touch water after a burn, otherwise they will blister. In fact, the reason for the burn and the depth of the burn have nothing to do with whether or not the burn is in contact with cold water. I degree burns damage light, exudate less, Ⅲ, Ⅳ degree burns damage deep, skin dehydration or dry necrosis, generally do not blister. Ⅱ degree burns due to more exudation, often blisters of varying sizes. I do not know that immediately after the burn with cold water rinse 15 minutes can make the trauma vasoconstriction, tissue fluid exudation less, in turn, can reduce the formation of blisters. And you can prevent the heat from continuing to act on the trauma to deepen it. At the same time, the nerve endings in the superficial layer of the dermis lose their epidermal protection after skin epidermal injury and are stimulated by cold, heat and harmful factors in the air. Cold therapy can make these nerve endings temporarily unconscious, producing a low-temperature anesthesia-like effect, thus reducing pain sensation.