Abstract: In order to investigate the factors influencing the moisture retentivity of tobacco leaf, the chemical compositions and tissue structure of different types of tobacco leaves, cuticular wax removed leaves and super-critical CO₂ extracted leaves on their moisture retentivity were analyzed. The results showed that:1) the moisture retentivity of flue-cured, burley and oriental tobacco leaves differed from each other because of their chemical composition and tissue structure differences; burley tobacco possessed higher moisture retentivity despite of it slower sugar content, which might be attributed to its unique tissue structure; 2) the reduction of moisture retentivity of flue-cured tobacco after washed by methylene chloride indicated that the cuticular wax played a crucial role in moisture retention of tobacco; 3) the enhanced moisture retentivity of super-critical CO₂ extracted flue-cured tobacco at low humidity condition demonstrated that the change of tissue structure was the key factor affecting its moisture retentivity; 4) water soluble sugars positively affected the moisture retentivity of burley tobacco at low humidity condition, but negatively affected the same at high humidity condition.