Solid shadow of lung tissue may suggest the possibility of pneumonia, pneumoconiosis, lung tumor, etc., and should be consulted in time. 1. Pneumonia: mainly inflammatory lesions in the lungs caused by bacterial and viral infections, patients mainly manifest symptoms such as cough, fatigue, muscle pain and so on. The diagnosis can be made by lung CT and chest X-ray film with high density shadow. 2. Pneumoconiosis: mainly caused by inhalation of mineral dust, pulmonary fibrosis, cough, sputum, shortness of breath and other symptoms. Small round or irregular shadows with high density can be observed on chest X-ray. 3. Lung tumor: the etiology is more complicated, which may be caused by low immunity, infection, smoking and other factors, with no obvious symptoms in the early stage, and with the progression of the disease, symptoms such as coughing, coughing up sputum and chest pain may appear. Imaging CT of the chest may reveal solid shadows in the lungs. Solid shadows in the lung tissue can also be seen in immune diseases such as systemic lupus erythematosus. Patients should be diagnosed by a professional doctor in conjunction with medical history, symptoms, signs and other relevant examinations to avoid delay.