Fibrotic nodules in lungs are not necessarily early stage lung cancer. Fibrotic nodules in lungs are mainly caused by pneumoconiosis or chronic interstitial pneumonia. 1. Pneumoconiosis: referred to as pneumoconiosis, it is mainly caused by long-term inhalation of mineral dust in occupation, which stays in the lungs and leads to diffuse lung tissue fibrosis. It leads to symptoms such as dyspnea, cyanosis, hemoptysis, etc. CT mainly shows that there are granular or small nodular shadows on the diffuse reticulated fibrosis shadow, which is called reticulated lesion. 2.Chronic interstitial pneumonia: with shortness of breath, cough, nasal flap as the main symptoms. It mainly involves bronchial tubes and alveolar septa, etc. Chronic patients have different degrees of fibrous connective tissue hyperplasia. Imaging manifestations are diffuse reticular shadows in the lung field and pleural thickening of the interlobular septa. Diffusely distributed small flaky or fibrous nodular shadows are seen in both lungs. Fibrotic nodules can be caused by a variety of diseases, and should be promptly examined in the hospital to determine the cause of the disease, so as to avoid delays.