A lung nodule of 10mm is not necessarily an early stage of lung cancer. Lung nodules are found on chest X-ray or CT scan and can be single or multiple. It may be scarring in the lungs after trauma, inhaled dust, after pneumonia or tuberculosis, all of which are benign nodules. However, lung nodules are not always benign. Lung nodules of different densities can be highly suspicious of malignant nodules depending on their size and shape. Lung cancer high-risk nodules are commonly found in: (1) solid lung nodules, with a diameter larger than 1.5cm or with a diameter of 0.8~1.5cm and showing lobulation, burrs, etc.; (2) partially solid lung nodules, with a diameter larger than 0.8cm; and (3) lung ground-glass-like nodules: with a diameter larger than 0.8cm. If there is a lung nodule of 10mm, and there is long-term smoking, family history of lung cancer, other lung diseases, etc., lung cancer should be highly suspected, and it is necessary to go to the hospital at the first time to clarify the nature of the nodule, early diagnosis and early treatment.