In order to research the changing trend of TSNAs contents in burley tobacco in process of threshing and redrying, five modules of burley tobacco were taken in process of crude tobacco, first conditioning, second conditioning, threshing and redrying. Routine chemical components and TSNAs contents of the samples were analyzed using SPSS and MINITAB. The results showed that the contents of TSNAs increased significantly in the threshing, but decreased in the redrying. Among them, NNN, NAT and NAB increased significantly, and NNK increased slightly but without any significant difference compared with crude tobacco in this whole process. Test for correlation coefficient showed that the relationship between TSNAs and routine chemical components did not display notable linear correlation. Therefore，threshing is considered the most important period in TSNAs control.