Abstract: To investigate the effects of Exobasidium vexans liquid culture on the growth and physiological characteristics of tobacco seedlings, experiments were carried out to study the effects of different concentrationsthe original solution, 1/10 original solution, 1/50 original solution,1/100 original solutionof E. vexans liquid culture on growth of leaves, stems and roots, chloroplast pigment, nitrate reductase (NR) activity and root activity of tobacco seedlings. On the 5th day, the maximum leaf length and root fresh mass of the 1/50 original solution were significantly different from that of the original solution, and the stem height, shoot fresh mass and content of Chl b were significantly higher than those of other treatments and the control. On the 10th day, the maximum leaf length and width, leaf area, stem height, stem circumference, chlorophyll a and carotenoid content of 1/50 original solution were the highest with significant difference from the original solution, 1/100 original solution and the control. The NR activity and root activity of 1/50 original solution were the highest and significantly higher than the original solution and the control. On the 15th day, the maximum leaf length and width, leaf area, stem height, shoot fresh mass, NR activity and root activity of 1/50 original solution were the highest with significant difference from the other treatments and the control. But the stem circumference, root fresh mass and chlorophyll a content of 1/50 original solution were significantly higher than that of the original solution, 1/100 original solution and control. The effects of different concentrations of E. vexans liquid culture were different on the growth and physiological characteristics of tobacco seedlings. The growth of tobacco seedlings was the best in 1/50 original solution.