Abstract: The pH values of 210 redried flue-cured tobacco samples were determined and the difference of pH values between tobacco leaves of different crop years, growing areas, stalk positions, grades and colors was analyzed. The result showed that: 1) the pH values of samples from different growing areas ranged between 4.8 and 5.4, with small variation coefficients; 2) the pH values of tobacco leaf decreased with the progress of aging, and the pH values of leaves cropped in years 2002 and 2003 differed extremely significantly with those of leaves cropped in 2001, 2000 and 1999; 3) the pH values of 2000, 2002 and 2003 leaves from different growing areas differed significantly or extremely significantly; 4) the pH values of 1999, 2000 and 2001 leaves from different stalk positions or of different grades did not show significant difference, while those of 2002 and 2003 leaves did; 5) the pH values of 2001, 2002 and 2003 leaves of different colors differed significantly, while those of 1999 and 2000 leaves did not; generally, the pH value of lemon leaves was higher than that of orange leaves.