A lung nodule of 13mm is not necessarily cancerous, and a comprehensive judgment is needed based on the nature and evolution of the nodule. Lung nodule is a kind of imaging description, although the probability of malignancy is relatively high if the nodule is larger than 8mm, but we can not judge the benign or malignant nature of the nodule simply based on this. Lung nodules can be infected nodules caused by pneumonia, tuberculosis nodules, or interstitial lung disease, and some may be tumor nodules. If the imaging of 13mm lung nodule shows lobular, burr-like, vascular signs, pleural pulling and other signs, or if the patient has no special symptoms, but the nodule is found to be progressing and enlarging with increasing solid component in the follow-up examination, then it is considered that the nodule has a high probability of cancerous transformation, and it needs to be resected as soon as possible to clarify the pathologic diagnosis and to determine the further treatment. There is no need to be too nervous and anxious when lung nodules are diagnosed, and it is recommended to consult a doctor in time for standardized diagnosis and treatment.