Fibrous foci in the lower lobe of the left lung are most often seen as a result of incomplete resorption of a chronic infection in the lungs, leaving a lesion on imaging. If the fibrous foci in the lower lobe of the left lung present as limited changes, they do not require special management, are most often the result of residual localized chronic infection, and generally do not cause recurrence or exacerbation. However, if the fibrotic lesions in the left lower lung increase extensively, one needs to be alert to pulmonary fibrosis and early alveolar carcinoma. If the pulmonary fibrosis is not controlled early, it will also cause a decline in lung function, leading to type I respiratory failure and hypoxemia, which will require long-term oxygen intake and ventilator treatment. If the fibrotic lesions are accompanied by coughing up a large amount of white foamy sputum, even with blood in sputum, and body weight is thin, early alveolar cancer should be alerted, and further fiberoptic bronchoscopy is needed to find out the cancerous cells, and targeted treatment should be given under the guidance of the doctor.