Abstract: In order to investigate the relationships between chemical components in flue-cured tobacco and components in mainstream cigarette smoke (MS), the routine chemical components (nicotine, total sugar, reducing sugar, total chlorine, total potassium and total nitrogen) in leaf samples of 6 flue-cured tobacco varieties from 26 tobacco growing areas and imported flue-cured tobaccos, the components (total particulate matter, nicotine, moisture content, tar and carbon monoxide) in MS and the puff number of cigarette were determined, and their relationships were studied with correlation analysis, partial correlation analysis and path analysis. The results showed that:1) Simple correlation analysis suggested that the total particulate matter, nicotine and tar delivery in MS significantly correlated with nicotine, potassium and chlorine in leaf. The delivery of carbon monoxide in MS significantly positively correlated with nicotine in leaf, while extremely significantly negatively correlated with potassium in leaf. The puff number of cigarette significantly correlated with total sugar, reducing sugar and total potassium in leaf. 2) Partial correlation analysis suggested that the total particulate matter, nicotine and tar delivery in MS only significantly correlated with nicotine in leaf. The delivery of carbon monoxide in MS and the puff number of cigarette significantly negatively correlated with total potassium in leaf. 3) Regression analysis and path analysis indicated that the total particulate matter, nicotine and tar delivery in MS were mainly affected by nicotine in leaf, next by potassium; which were indirectly affected by total nitrogen through nicotine in leaf. The delivery of carbon monoxide in MS was mainly influenced by total potassium in leaf. The puff number of cigarette was indirectly affected by reducing sugar through total sugar. In conclusion, the components in MS were greatly affected by nicotine and total potassium in leaf.