Abstract: The relationship between Election Conductivity value and the contents of Soluble Sugar, Soluble Protein, Free Praline, MDA and Root Vigor in tobacco seedling under different Iron nutrition levels (0.00、0.56、1.12、1.68、3.36、4.48mg/L) using liquid culture was evaluated. The results showed that under Fe 1.68mg·L-1 treatments, the plant height and root/shoot value of tobacco leaves were better than those of the other treatments; but the Election Conductivity content, Free Praline, and MDA content were lower, while Soluble Sugar, Soluble Protein, Root vigor of tobacco were higher than those of the other treatments.