Solid nodules in the lungs are classified as ground glass nodules, partially solid nodules, and solid nodules. Solid nodules in the lungs are mostly seen in inflammatory pseudotumors, tuberculosis spheres, and foci of calcification, and foci of proliferation due to tuberculosis are also considered solid nodular foci in the lungs. Inflammatory pseudotumors in the lung are mainly tumor-like foci caused by incomplete absorption of chronic pneumonia, which generally do not intensify after enhanced CT chest examination and can be treated surgically if chronic lung inflammation is indicated by percutaneous pulmonary puncture. In contrast, tuberculosis spheres are mostly solid lesions formed by incomplete absorption of tuberculosis, and the lesions are usually not infectious, and poor anti-tuberculosis effect requires thoracic surgery to remove the lesions. In conclusion, solid nodules in the lung are mostly benign, unless they are larger than 3 cm with lung cancer manifestations such as short burr, lobulated, pleural depression sign, etc., and need surgical resection treatment.