Abstract: In order to investigate the relationships between stalk positions and the deliveries of 7 harmful compounds,including CO,HCN,NNK,NH₃,BaP,phenol and crotonaldehyde,in mainstream cigarette smoke, cigarettes of the same hardness made of each single grade of K326 tobacco leaves from Yuxi in Yunnan and Xuchang in Henan were determined. These harmful compounds in leaves and in mainstream cigarette smoke were analyzed. The results showed that:1)The contents of harmful compounds in mainstream cigarette smoke changed with the stalk positions of tobacco leaves. 2) The variation of harmful compound 's delivery in mainstream cigarette smoke was mainly caused by the difference of tissue structure and chemical composition in tobacco leaf and the puff number of cigarettes. 3)Reasonably proportioning of tobacco leaves from different stalk positions in cigarette could selectively reduce the release of the said harmful compounds except for NNK.