The eighth edition of TNM staging criteria for lung cancer is based on three indicators: primary tumor, lymph node metastasis and distant metastasis. Lung cancer is a common malignant tumor of the respiratory system, which can be caused by various factors such as smoking, heredity, etc. TNM staging is a commonly used clinical staging table to judge the severity of the disease, to guide clinical treatments, and to judge the prognosis of the disease. The staging criteria are: T primary tumor development, N lymph node metastasis, M whether distant metastasis occurs. T0 means no evidence of primary tumor, T1 means that the diameter of tumor is less than or equal to 3cm and does not invade the main bronchus, T2 means that the maximum diameter of tumor is between 3-7cm and invades the dirty pleura, T3 means that the diameter of tumor is more than 7cm and invades the chest wall and phrenic nerve, etc. T4 means that regardless of the size of the tumor, it invades the heart and the main bronchus, etc. T4 means that the tumor has invaded the heart and the main bronchus. N0 represents no lymph node metastasis, N1 represents peribronchial or ipsilateral hilar lymph node metastasis, N2 represents ipsilateral mediastinal and infratentorial lymph node metastasis, N3 represents contralateral hilar, mediastinal or supraclavicular lymph node metastasis. M represents distant metastasis, M0 represents no distant metastasis, and M1 represents distant metastasis. TNM staging can be divided into stages I~IV, in which the later the staging, the more complicated the condition, the more serious the disease and the worse the prognosis. When lung cancer occurs, one should actively consult the doctor and follow the doctor’s instructions for reasonable treatment.