Abstract: The pH values of the aqueous infusion of 49 kinds of tobacco fine and the aqueous infusion of Zhaoyang B2F fine added with NaOH or HCl were determined, nicotine in the infusions was distilled with steam, and the content of total nicotine was determined.The results showed that:1) the pH value and nicotine content varied with the grade and growing area of leaf;2) there was no significant correlation between the pH value of aqueous infusion of tobacco fine and nicotine distillation yield, while the pH value linearly positively correlated with nicotine distillation rate, and the correlation coefficient was 0.935;3) when the pH value of aqueous infusion of B2F fine was between 1.93-5.32, the nicotine distillation rate was 0-10.85% and increased flat with the increase of pH value;when the pH value was between 5.32-9.07, the distillation rate was 10.85%-86.33% and linearly positively correlated with pH value(r=0.995);when the pH value was between 9.07-10.93, the distillation rate was 86.33%-92.79%, and their relationship curve became flat again.