The tar yield and the contents of 25 chemical components in 182 samples of cured tobacco leaves were determined, the multiple stepwise regression equation of tar yield versus the contents of those chemical components was developed, the correlations between tar yield and contents of the chemical components in tobacco leaf were analyzed by correlation analysis, stepwise regression analysis and path analysis. The results showed that: 1) The contents of total sugar, potassium, moisture, cellulose, succinic acid, malic acid, palmitic acid, oleic acid, linolenic acid and stearic acid extremely significantly negatively correlated with tar yield, while the contents of total nitrogen, nicotine, volatile alkali, protein, rutin and malonic acid extremely significantly positively correlated with tar yield. 2) Malonic acid, stearic acid, total sugar, nicotine, potassium and malic acid were the important components affecting tar yield. The correlation of malonic acid, stearic acid and total sugar with tar yield were the results of joint actions of direct and indirect effects, however direct effect was more important; the correlation of nicotine, malic acid and potassium with tar yield was mainly the result of direct effect.