The disease should be differentiated from chronic bronchitis, tuberculosis, lung abscess and other diseases. 1. Chronic bronchitis patients with chronic bronchitis mostly have cough and sputum symptoms in spring and winter, with white mucus foamy sputum, and the age of onset is mostly in middle and old age. Advanced patients are often accompanied by bronchial dilatation. 2, tuberculosis early tuberculosis patients cough light, sputum is not much, with the cavity of the sputum is often mucus-like or purulent, sputum examination can be detected more tuberculosis bacteria. The whole body condition may be accompanied by weakness, emaciation, low fever in the afternoon, night sweating and other symptoms. 3.Lung abscess has the clinical manifestations of rapid onset, chill, high fever, cough, and large amount of yellow or yellow-green pus sputum. The lung lesion is characterized by turbid percussion, decreased breath sounds and wet rales, and a cavity with fluid level and dense inflammatory shadows around the cavity can be seen on X-ray.