When tiny nodular foci in lung are found after colon cancer surgery, it is necessary to improve relevant examinations to clarify the nature of the foci and carry out treatment under the guidance of specialists. If tiny nodule foci are found in lung after colon cancer surgery, it is recommended to improve tumor markers, chest CT scan + enhancement and other examinations under the guidance of specialists. If it is lung metastasis of colon cancer: lung metastasis can occur after colon cancer surgery, if the tiny nodules in lungs are new and tumor markers such as CEA are obviously elevated after colon cancer surgery, chemotherapy such as capecitabine and oxaliplatin can be carried out in clinical judgment of lung metastasis of colon cancer. If the nature of lesions cannot be clarified: if patients have no clinical symptoms, no obvious changes in chest CT, and no obvious elevation of tumor markers compared with the preoperative period, it is difficult for clinicians to judge the nature of lung micronodules, and it is recommended that patients undergo chest CT, tumor markers and other examination and monitoring once every 2~3 months. If necessary, lesion puncture cytology is needed to clarify the nature of nodule lesions. It is recommended that patients with postoperative lung micronodules of colon cancer should confirm the treatment plan under the guidance of specialists and avoid blindly using drugs by themselves.