The severity of a 0.7cm nodule in the lower lobe of the left lung needs to be considered based on the benign or malignant nature of the nodule; a malignant nodule is a more serious one, while a benign nodule may not require treatment. A 7mm nodule in the lower lobe of the left lung is more likely to be benign, but it needs to be considered in the context of specific clinical manifestations, signs, and imaging features of the nodule. If physical examination reveals a 0.7cm nodule in the lower lobe of the left lung, and there is a long history of coughing and sputum with blood in the sputum, or the nodule is found to be lobulated, burr-like, or the pleura is stretched on imaging, even if there is no symptom, it is considered to have a high possibility of malignancy, and it is necessary to perform surgical resection at the earliest possible time to clarify the nature of the nodule and to decide on the follow-up treatment, or else it may lead to serious consequences. If such a nodule is present in previous physical examination and there is no significant change in the nodule on regular review, it is likely to be benign and not serious, so it can be left untreated and the patient can continue to undergo regular review. In the case of a 0.7 cm nodule in the lower lobe of the left lung, it is recommended that the thoracic surgery clinic be consulted for standardized treatment as prescribed by the doctor.