Abstract: 66 samples of 3 grades(B2F, C3F, X2F) of K326, a flue-cured tobacco cultivar widely planted in Hunan Province, were selected to determine their physical traits and tar yield and to analyze the relationship between physical traits and tar yield with correlation analysis, path analysis and stepwise regression analysis.The results showed that tar yield had extremely significant positive correlation with single leaf weight, weight per leaf area and leaf thickness, while had extremely significant negative correlation with leaf openness and midrib content.The physical traits in the order of effectiveness on tar yield were single leaf weight> weight per leaf area> leaf openness> equilibrium moisture content> midrib content> leaf thickness.The effects of leaf thickness and midrib content on tar yield were mainly indirect, while the effects of leaf openness and equilibrium moisture content on tar yield were mainly direct.The single leaf weight and weight per leaf area not only imported strong direct effects on tar yield, but also assisted the other physical traits to strengthen their indirect effects.The multiple stepwise regression equation of tar yield versus physical traits was also developed.