Pulmonary encephalopathy, also known as pulmonary heart-brain syndrome, is a brain tissue damage and cerebral circulatory disorders caused by chronic bronchitis complicating emphysema, pulmonary heart disease and pulmonary failure. The diagnosis is mainly based on the presence of chronic lung disease with pulmonary failure; clinical manifestations of consciousness disorders, neurological and psychiatric symptoms and localized neurological signs; pulmonary insufficiency and hypercapnia in blood gas analysis; and exclusion of neurological and psychiatric disorders caused by other reasons. The principles of treatment are as follows: 1. firstly, various chronic respiratory diseases should be treated; 2. control respiratory infections and reasonably apply antibiotics; 3. improve respiratory function, hypoxia and carbon dioxide retention; 4. correct acid-base balance disorders; 5. treat neurological and psychiatric disorders symptomatically.