Pneumonia is a more common disease in 3-year-old children, and aggravation of the disease can lead to cardiopulmonary failure, etc. Therefore, hospitalization is usually required to facilitate observation and judgment of the condition and avoid delayed treatment. Pneumonia, i.e. bronchopneumonia, refers to the inflammation involving the bronchial walls and alveoli, and is a relatively common disease in young children, often caused by viral, bacterial or Mycoplasma pneumoniae and other pathogenic infections. Clinical symptoms such as recurrent fever, coughing or wheezing may be present, and chest radiographs may assist in the diagnosis. Complications (e.g., pyothorax, pneumothorax, lung abscess, or cardiopulmonary failure) are rare after early and rational treatment. However, if the diagnosis is delayed or the pathogen is highly pathogenic, the above complications may occur and may even be life-threatening. Therefore, hospitalization is usually recommended, and specialists can better observe and judge the development of the disease, which will help in the treatment of the disease. It is recommended to actively consult a doctor and follow the doctor’s instructions.