Objective       To investigate the metastatic characteristics of lung cancers with stage Ⅳ based on the results of PET/CT scanning.       Methods       The PET/CT data of 631 patients with definite pathologically diagnosed stage Ⅳ lung cancer in our hospital during the years of 2008 to 2013 were collected. The metastatic rates of different pathological types of lung cancer were analyzed and compared statistically.       Results       In the enrolled 631 patients with advanced lung cancer

the incidence of hilar lymph node metastasis were significantly higher

and that of mediastinal and supraclavicular lymph nodes metastasis were significantly lower in small cell lung cancer (SCLC) and squamous cell carcinomas (SCC) than adenocarcinoma(AC)(both P0.01). The incidence of abdominal lymph node metastasis was significantly lower in SCLC and AC compared with SCC (P0.01). The rates of pleura

brain and bone metastasis were significantly higher in the patients with AC than those with SCLC or SCC (pleura P0.05

brain P0.01

bone P0.01). The rate of liver metastasis was significantly higher in patients with SCLC compared with AC and SCC (P0.05). The rate of adrenal metastasis was significantly lower in the patients with SCC compared with SCLC and AC (P0.05). The most common bone metastatic sites were spine.       Conclusion       PET/CT scanning is of higher value for the diagnosis of stage Ⅳ metastatic lung cancer patients. The metastasis of lung cancer is significantly associated with histological types. We should pay close attention to AC because of its highest incidence of cancer metastasis

most widely metastatic sites

and easier to violations of human vital organs.