Hypercapnia is mainly caused by insufficient ventilation of the respiratory system or excessive carbon dioxide retention. It can be seen in lung infection, bronchial asthma, chronic obstructive pulmonary disease, etc. At this time, we should timely repeat the arterial blood gas analysis to monitor the changes of vital signs; appropriately give a diet high in protein, vitamins, and fiber; continuous oxygen therapy to keep the airway open; if necessary, we can carry out endotracheal intubation or mechanical ventilation of the ventilator, to improve the respiratory function of the lungs. Symptomatic treatment, to prevent the emergence of brain tissue edema, intracranial hypertension and other complications, combined with bacterial infection need to actively use antibiotic treatment.