Abstract: In order to investigate the effects of growing area and stalk position of tobacco leaves on the releases of tar and seven harmful components in mainstream cigarette smoke, 467 flue-cured tobacco samples from different stalk positions were collected from representative tobacco planting areas in China. The releases of tar, seven harmful components and nicotine in the mainstream smoke of cigarettes made of single-grade tobacco were determined. The effects of growing area and stalk position of tobacco leaves on the Hazard Index of cigarette smoke and the releases of tar, seven harmful components and nicotine in mainstream cigarette smoke were studied. The results showed that:1) On per mass unit cut tobacco basis, growing area affected the release of NNK most significantly, followed by the releases of ammonia, HCN and phenol, its influences on tar, Hazard Index, nicotine, BaP, crotonaldehyde and CO were less. 2) On per unit nicotine basis, growing area influenced the releases of ammonia and NNK most significantly, followed by HCN, crotonaldehyde, BaP, phenol and CO, its effects on tar and Hazard Index were less. 3) On per mass unit cut tobacco basis, stalk position significantly influenced the releases of ammonia, nicotine, phenol and NNK, and slightly influenced Hazard Index and the releases of tar, HCN, BaP, crotonaldehyde and CO. 4) On per unit nicotine basis, stalk position significantly affected the releases of crotonaldehyde, CO, NNK, BaP and HCN, and slightly influenced Hazard Index and the releases of tar, ammonia and phenol. Adjusting the proportions of leaves from different areas or stalk positions in cigarette blend could reduce the releases of tar and seven harmful components on per mass unit cut tobacco basis or per unit nicotine basis.