The TNM staging of lung cancer which is now widely used in clinic was formally proposed in 1997. It has played quite an important role in directing the diagnosis and treatment of lung cancer as well as the clinical research in the past decade. However, at the same time, there are some insufficiencies which are emerging gradually. By collecting the clinical information from 100 869 patients, in 2007, International Association for the Study of Lung Cancer(IASLC) made a deep analysis on the relativity between TNM staging and prognosis, and put forward the suggestions to revise the Seventh Edition of the TNM staging of lung cancer: (1) According to the size of tumor, the primary T staging is divide into T1a (the maximum tumor diameter≤2 cm), T1b (3 cm≥the maximum tumor diameter＞2 cm), T2a (5 cm≥the maximum tumor diameter＞3 cm) and T2b (7 cm≥the maximum tumor diameter＞5 cm); (2) T 2c (the maximum tumor diameter gt;7 cm) and additional nodules in the same lobe are classified as T3, while nodules in the ipsilateral nonprimary lobe are classified as T4;(3) Cancerous hydrothorax, pericardial effusion and the additional nodules in the contralateral lung are classified as M1a, while the extrapulmonary metastases are classified as M1b. It is believed that the new revised edition will has higher international authority and identification degree, and it will play a more meticulous and accurate guiding role in the treatment of lung cancer and its predicting prognosis in the future. At the same time, it will provide a new starting point to the research of lung cancer.