Lung masses are defined as masses larger than 3 cm in diameter and less than or equal to 3 cm are collectively referred to as nodules, and the size of nodules or masses in the lung is closely related to their malignancy,>93%-97% for 3 cm masses, 64%-82% for 2-3 cm nodules; 0.5 -1.0 cm was 6%-28%; <0.5 cm was 0-l%. The size of the mass >3cm, the possibility of malignancy is greater, but the differential diagnosis of its malignancy still needs to be analyzed by the morphology, margin, and nature of the mass, and it is best to continue to improve other auxiliary examinations, such as positron emission computed tomography (PET-CT), bronchoscopy, and tumor markers to assist in the diagnosis. However, only pathological examination is the most accurate means to confirm the diagnosis of lung cancer.