Newborn babies, especially premature babies, will have poor thermoregulatory function and immature development of the thermoregulatory center, which will cause hypothermia or fever when the degree of environmental temperature change exceeds the baby’s own thermoregulatory ability. The normal body surface temperature of newborns is 36.0～36.5℃, and the normal core (rectal) temperature is 36.5～37.5℃. Neonates have no chilling response when cold and rely on brown fat chemistry for heat production. Premature infants have less brown fat and poor thermogenesis, and are more likely to have hypothermia and even sclerosis when cold. High ambient temperature, low water intake and insufficient heat dissipation can increase body temperature and lead to dehydration fever. Be careful not to cover the child too much, many parents love their children, the child’s warmth measures are often too much, the child wrapped up tightly. In fact, this has fewer advantages and more disadvantages, when the temperature inside the quilt exceeds 34 ℃, the newborn will occur hyperthermia, a lot of sweating, resulting in a large loss of extracellular fluid, resulting in dehydration, metabolic acidosis, cerebral hypoxia and cerebral edema and a series of adverse consequences, medically known as infantile smothering syndrome. In principle, it is appropriate to keep the newborn baby warm with a normal complexion, warm extremities and no sweating. If the newborn behaves abnormally, has sweat on his face, breaks free from the bun, stretches out his arms outside the bun, and his body temperature is above 37.5℃, it indicates that the warmth is too much and should be reduced by some clothes. If the child’s hands and feet are cold and the body temperature is less than 36℃, it means that the warmth is not enough, so it is necessary to increase the clothing and quilt and raise the room temperature.