Flue-cured tobacco leaves from cultivar Honghuadajinyuan graded B3F(upper leaves), C3F(middle leaves) and X2F(lower leaves) were chosen to investigate the effects of various threshing and redrying processes on the delivery of HCN, benzo[a]pyrene and crotonaldehyde in cigarette mainstream smoke. The results showed that the HCN delivery from upper leaves was the highest, while the lowest from the lower leaves. The HCN delivery of upper leaves got substantial increase after the first conditioning process, compared to which the benzo[a]pyrene delivery of lower leaves was reduced by 9.36% after the second conditioning process. The crotonaldehyde delivery of the lower leaves was reduced by 14.96% and the benzo[a]pyrene delivery of middle leaves was reduced by 17.29% after redrying process compared to those after the second conditioning process. The change intensity of the delivery of 3 components from the upper leaves was significantly bigger than that from the lower leaves after each process step.