Small pulmonary nodules and foci of small pulmonary nodules belong to the same kind of description in CTology and are mainly seen as abnormal changes described in CT of the chest. Small pulmonary nodules are classified into 3 types: ground glass nodules, partially solid nodules, and solid nodules. If the small nodules are smaller than 5 mm, they are mostly benign chronic inflammatory changes and can be treated without specific treatment if there are no clinical symptoms. If small nodules and small nodular foci are above 6-8mm, especially small pulmonary nodules larger than 8mm on the lung with short burr, lobar, pleural traction sign, pleural depression sign and other changes, be alert to the occurrence of early lung cancer. Give an enhanced CT examination of the chest and, if necessary, a percutaneous lung puncture cytologic biopsy to find out whether early lung cancer has occurred. Once the diagnosis is confirmed, a thoracic surgeon can be asked to remove the lesion as soon as possible to avoid any missed diagnosis or misdiagnosis.