After a burn injury occurs, what measures should be taken by the casualty and other personnel at the scene to effectively stop the continued development of the injury, so that the casualty can be protected and receive simple, emergency treatment, or safe transfer, are all part of first aid at the scene. The principles of first aid are rapid removal of the source of injury, termination of the burn, removal from the scene, and prompt and appropriate treatment. The importance of on-site first aid is that it can effectively reduce the degree of injury, reduce patient suffering, and reduce complications and mortality. On-site first aid for burn patients is the beginning and foundation of burn treatment, and has a very important impact on subsequent treatment and patient’s life safety. How to perform on-site first aid when thermal burns occur? Thermal burns generally include burns caused by hot water, hot liquid, steam, flame and hot solid, as well as radiation, and they occur most often in daily life, so there are a variety of folk “first aid” measures, the most common of which is to apply toothpaste, soy sauce, and even alkali powder to the trauma; there are also flame burns in which the injured person runs and shouts to put out the fire by hand In the case of oil burns, the use of water to put out the fire, etc., these practices are not correct, the consequences are often counterproductive, and even make the injury more serious. Effective measures to immediately remove the injury-causing factors, and to give cooling. Such as hot liquid burns, should immediately remove the impregnated clothing, so that the heat no longer continue to act, and as soon as possible with cool water rinse or soak, so that the wounded part of the cooling, reduce pain and injury degree. When the flame burns, do not run, shout, to put out the fire with your hands, so as not to help the fire burn and cause head and face, respiratory and hand burns. Should roll in place, or cover the fire part with quilts, blankets, etc., suitable for flushing, to water to put out the fire, but also jump into the nearby pool or ditch to put out the fire; not suitable for flushing, with fire extinguishers. Hot solid burns, such as hot stoves, hot water bags, hand warmers, etc., should be immediately removed from the heat source. After removing the injury-causing factors, the trauma surface should be flushed with cold water. This has the advantage of controlling the local pathophysiological process, reducing local damage and alleviating pain. The lower the water temperature, the better the effect, which should be at least below 15°C and last as long as possible, usually not less than 15 minutes. The water temperature and time of cold water rinsing should be combined with the season, room temperature, burn area, and physical condition of the injured person. Low temperature, large burn area, old and weak, will not be able to tolerate a larger body surface area of cold water flushing. After rinsing the wound, do not apply it freely. Even some topical medications such as gentian violet and red mercury, which are commonly used in primary care units and at home, should not be used, because topical medications with staining effects can affect the diagnosis of the area and depth of the burn after application, and also affect the observation of the inflammatory reaction and the condition of the wound in subsequent treatment, and there are side effects of mercury absorption poisoning from the topical use of red mercury in large quantities. Before being sent to the hospital, the wound can be covered with a sterile dressing or, if not available, with a clean sheet or quilt, avoiding direct contact with the outside world as much as possible.