Abstract： Objective To investigate the related factors of lung metastasis of differentiated thyroid carcinoma,to predict the occurrence of lung metastasis,and to diagnose it early. Methods A retrospective study was performed on 405 cases of DTC patients who were admitted from July 2016 to June 2018. General and clinical data of the patients were collected,including gender,age,clinic pathologic type,occupation,en-vironmental status,primary lesion size,TSH inhibition and gene mutation. Single factor analysis of log-rank and multiple logistic regression analysis were performed. The regression equation was established based on the results of multiple regression analysis, and the prediction accuracy of the equation was tested. Results Among 405 DTC patients,68 had lung metastasis. Univariate analysis showed that smoking and secondhand smoke exposure,occupational exposure,body mass index,pathological type,number of primary lesions,invasion of extraneous thyroid tissue and mediastinal lymph node metastasis were 7 significant fac-tors influencing lung metastasis of DTC. Multiple Logistic regression analysis suggested that the pathological type,number of primary lesions,mediastinal lymph node metastasis and body mass index were independent factors influencing lung metastasis of DTC (P<0. 05). Conclusion Pathological type,number of primary lesions,mediastinal lymph node metastasis and body mass index are the related factors affecting DTC lung metastasis. In view of this kind of patients,clinical attention should be strengthened to improve the regular review and follow-up work.