Clinically, respiratory failure is categorized into type I and type II expiratory failure according to the values of partial pressure of oxygen and partial pressure of carbon dioxide, with different diagnostic criteria. Type I respiratory failure is defined as arterial partial pressure of oxygen <60mmHg, and partial pressure of carbon dioxide remains normal or is mildly reduced; type II respiratory failure is defined as partial pressure of carbon dioxide >50mmHg, and partial pressure of arterial oxygen <60mmHg. Respiratory failure can be categorized as acute expiratory failure, chronic expiratory failure, and acute exacerbation of chronic expiratory failure. Acute expiratory failure refers to respiratory failure caused by sudden factors. Chronic expiratory failure is respiratory failure combined with chronic lung disease. And acute exacerbation of chronic expiratory failure: patients with chronic expiratory failure experience severe hypoxia and carbon dioxide retention. Patients with respiratory failure need to keep the airway open, correct the acid-base imbalance and metabolic dysfunction caused by hypoxia and/or hypercapnia, and maintain stable circulatory function. If the patient appears uncomfortable symptoms, it is recommended to go to the hospital in time for a detailed examination to clarify the cause of the disease and then targeted treatment.