Abstract： Pneumoconiosis is characterized by chronic lung inflammation and fibrosis, and inflammation can promote pulmonary fibrosis, which in turn leads to pneumoconiosis. When a large shadow with a long diameter of not less than 2 cm and a short diameter of not less than 1 cm appears in the lung, it can be classified as stage Ⅲ pneumoconiosis. This paper reports a case of stage Ⅲ pneumoconiosis with a large shadow in the upper right lung accompanied by burr-like changes misdiagnosed as lung cancer by CT examination.When the large shadow lesions in patients with pneumoconiosis and lung cancer are difficult to distinguish on CT, an additional MRI examination, particularly T 2W imaging sequence is useful sequence for identifying the two.