Oxygen saturation is the percentage of hemoglobin that binds to oxygen and reaches saturation, depending on the partial pressure of blood oxygen. Low oxygen saturation is associated with infections, inability to discharge secreted sputum, inadequate ventilation, and heart disease. In this case, firstly, the infection is actively controlled and effective antibiotics are used. Secondly, encourage the patient to cough and carry out sputum treatment to promote the discharge of sputum. If the blood gas indicates simple hypoxia and carbon dioxide secretion is not high, oxygen can be administered by mask. If necessary, ventilator-assisted respiration and pure oxygen therapy can be given. In addition, keep indoor air circulation, exercise properly in general to improve respiratory resistance, pay attention to rest and prevent cold.