Fibrous bands in both lungs are often indicative of a previous lung infection, such as Mycobacterium tuberculosis infection, and tend to be old. Bilateral pulmonary fibrous bands are a characteristic feature of lung pathology detected by imaging. The more common pathogens are bacteria, Pseudomonas aeruginosa, and Mycobacterium tuberculosis. If tuberculosis caused by Mycobacterium tuberculosis is well controlled by standardized anti-tuberculosis treatment, the lesions will still be left with varying degrees of fibrosis and calcification after cure, which cannot be completely dissipated. Usually there are no clinical symptoms, no special treatment is needed, and regular review is sufficient. If imaging shows fibrous streaks in both lungs, and the patient is accompanied by symptoms such as cough, sputum, fever, etc., the patient should consult the doctor in time to find out the cause of the disease and treat it aggressively.