Intractable pneumonia generally refers to uncontrolled pneumonia after standardized anti-infective and other related treatments, which may be caused by weak immunity, serious condition, underlying diseases, drug-resistant bacteria infection or special bacteria infection, or non-infectious diseases. 1. Weak immunity, the effectiveness of pneumonia treatment has a close relationship with the immunity of the body, such as immunity is too poor, even after standardized treatment, the disease may gradually progress. 2. Serious condition. Mild pneumonia can be cured after standardized treatment in most cases, but serious condition can be combined with respiratory failure, septic chest and other complications, which can lead to serious consequences. 3. Underlying diseases, such as repeated aspiration of cerebrovascular disease, lung tumors leading to airway obstruction, etc., all of which may cause pneumonia difficult to cure. 4. Drug-resistant bacterial infections or special bacterial infections, which may be ineffective even if treated with broad-spectrum antibiotics. 5. Non-infectious diseases, such as cryptogenic mechanized pneumonia, chronic eosinophilic pneumonia, etc. Clinical symptoms, chest CT, etc. may be consistent with the manifestation of pneumonia, but anti-infective treatment is ineffective. Therefore, persistent pneumonia requires timely assessment of the causes of treatment failure and targeted management.