Multiple microscopic nodules in both lungs are usually detected by lung CT, which may be caused by past infections, long-term smoking, exposure to dust, air pollution or genetic factors, resulting in lung lesions and nodules with a maximum diameter of less than 5 mm. Most of the multiple microscopic nodules in both lungs are not very serious and belong to benign diseases, a few may be malignant tumors, but the specific severity still needs to be determined according to the condition. If the nodules are caused by lung diseases such as pneumonia or tuberculosis, they are benign nodules and can be treated with anti-inflammatory and anti-tuberculosis therapy as prescribed by the doctor. However, if the nodules are caused by metastatic cancer in the lungs or metastases from other parts of the lungs, they are malignant and usually require surgery, chemotherapy and radiotherapy, but the long-term effect is relatively poor. In addition, there are some unexplained multiple microscopic nodules in both lungs. It is necessary to pay attention to regular review and dynamically observe the changes of nodule size and shape, and if there is a trend of gradual increase, it is recommended to improve tumor markers, PET-CT and other examinations to help determine the nature of nodules, and if necessary, puncture examination.