The principle of oxygen administration for respiratory failure in pulmonary heart disease is continuous low-flow oxygen intake to prevent the blood oxygen level from being too high. 1. Continuous low-flow oxygenation: low-flow oxygenation can stimulate the patient’s peripheral chemoreceptors and increase the patient’s respiratory rate, thus increasing the patient’s ventilation, which will help the carbon dioxide to be discharged out of the body and correct the patient’s symptoms of carbon dioxide retention. 2. Prevent the blood oxygen level from being too high: too high oxygen concentration will inhibit the stimulation of peripheral chemoreceptors by hypoxia, aggravate carbon dioxide retention, and is not conducive to the treatment of respiratory failure. Patients should follow continuous low-flow oxygen intake under doctor’s guidance to prevent high blood oxygen level.