Abstract: In order to study the photosynthetic capacity of different tobacco varieties, with flue-cured tobacco varieties NC297, NC89, zhongyan100 as material, photosynthetic physiology index and photosynthetic pigments were studied by using the LI-6400 portable photosynthesis system. The photosynthetic light-response curve of different cultivars was alsosimulated.The results show that, (1) With increasing of light intensity the stoma conductance, net-photosynthetic rate and transpiration rate went up gradually while concentration of intercellular CO₂ concentration went down gradually; (2) zhong yan100 had the highest the light saturation point, the lowest the light compensation point and the dark respiration rates, NC297 had the highest the maximum photosynthetic rates, NC89 had the highest the apparent quantum yields; (3) the total contents of chlorophyll and carotenoids is the greatest for NC89 and smallest for zhongyan100, Chlorophyll a/b is the greatest for zhongyan100.