After malignant lung nodule is diagnosed, whether it is early stage of lung cancer or not should be analyzed in combination with lymph node metastasis and distant metastasis. Lung cancer is a malignant tumor caused by smoking, gene mutation and other factors. When malignant lung nodules appear, it is necessary to combine with lymph node metastasis and whether distant metastasis occurs to determine the stage. When the maximum diameter of the nodule is ≤1cm, confined to the lung and visceral pleura, without lymph node and distant metastasis, it is regarded as early stage. If the maximum diameter of the nodule is ≤1cm, confined to the lungs and visceral pleura, accompanied by ipsilateral hilar or bronchial lymph node metastasis, and without distant metastasis, it is regarded as intermediate stage. When distant metastasis occurs, the disease is considered to be in the advanced stage. It is recommended that the patient should consult the doctor in time, complete the relevant examinations to clarify the type and stage of the disease, and actively treat the disease to avoid delaying the condition.