There are three main reasons why children are prone to pneumonia: First, the anatomical structure of the child’s whistle is determined by the relatively small size of the trachea and bronchial lumen of children, and the lack of elastic tissue, smooth muscle is not well developed, the secretion of mucus is insufficient and dry, the mucosal cilia movement is poor, so the ability to remove microorganisms from the whistle is not strong. Children’s lung tissue also appears to have more air and less blood because of development, and bacteria are more likely to grow when they invade the lungs. Second, it is determined by the physiological characteristics of children Children’s whistling frequency is several times faster than that of adults, and the younger they are, the faster they are, so they lack the ability to compensate. In other words, once more oxygen is needed, the child’s whistling rate becomes short of oxygen supply because it cannot go any faster, and the lungs cannot cope with the extra burden after a whistling infection, which can be aggravated and difficult to control. Children also have relatively small lung volumes and ventilation, and their lungs are relatively deficient in oxygen, which is not conducive to the repair of lung tissue after injury. There is also a term that reflects the compensatory capacity of the whistle called “airway resistance”, the airway resistance of children is larger than adults, airway resistance and the size of the airway diameter, the diameter of the tube increases with development, the resistance decreases with age. In addition, infants and children with pneumonia, the airway lumen mucosa swelling, increased secretions, bronchospasm and other factors make the lumen more narrow, greater resistance, so prone to whistling failure. Third, the immune characteristics of children are determined by the human lymphoid tissue to produce antibodies is a powerful weapon to destroy or prevent infection by pathogenic microorganisms, but children’s immune function does not reach or approach adult levels until the age of 12. There is a type of antibody called “secretory IgA” that is particularly important in the defense of the mucous membrane of the whistle against microbial infections, but unfortunately the level of this antibody is very low in newborns and infants, which is another important reason for vulnerability to infections. Breastfed children can obtain such antibodies from breast milk, whereas children who eat formula milk can only produce them on their own, making artificially fed children more susceptible to whistle infections. Children have a fragile body structure and function that can only be overcome slowly by development, but with a scientific approach to parenting and a focus on exercise from an early age, deficiencies can be maximized to prevent pneumonia from occurring.