Pulmonary 3mm micro nodules are mostly benign and do not require special treatment. They are commonly found in people with long-term smoking and exposure to dust, including masons, coal miners, chefs, hairdressers, tailors and other jobs, which are prone to the formation of micro nodules on the lungs. Once the nodule is formed, its nature needs to be further clarified. If the nodule has no significant changes in 1 year of follow-up by chest high-resolution CT examination, the 3mm micro nodule is mostly benign nodules and does not require special treatment or drug treatment. If the 3mm nodule grows to 5mm or 8mm after 1 year, it is no longer a benign nodule. At this time, further chest enhancement CT examination is needed to clarify whether the nodule has become cancerous, and further surgical intervention can be requested from the thoracic surgeon.