Pulmonary nodules are divided into two categories: benign nodules and malignant nodules. If the nodules are benign, they are usually not cancerous and there is no need to worry too much. Under normal circumstances, there are many causes of lung nodules, most of which are benign lesions, such as tuberculosis and trauma to the lung. If the nodules in the lung are less than 1 cm and the edges are relatively clear, most of them are benign lesions, and if there is calcification, the possibility of benign is even higher. Patients are advised to have a follow-up examination once every 6 months, and the observation period can be 3-5 years. In addition, some nodules caused by inflammation, tuberculosis and fungal infection can be completely cured with active anti-infection and anti-tuberculosis treatment and will not become cancerous. If patients have larger nodules with unclear edges or burrs and irregularities, they should be alerted to their possible malignancy and further pathological examination is recommended for clarification. In addition, people with long-term infection or long-term smoking can also lead to nodules smaller than 3 cm in the tissues of the lungs and should pay attention to prevention.