Effect of 0 (CK), 1, 3, 5 and 7 g·L^-1  NaCl stress on relative conductivity and contents of MDA, proline, soluble protein and soluble sugar in leaf of Fraxinus americana Linn. seedling was studied by nutrient solution culture method. Results show that with rising of NaCl mass concentration, relative conductivity and contents of MDA and proline in leaf all are gradually increasing and are higher than those of the control; soluble protein content appears a fluctuation trend with lower content under 7 g·L^-1 NaCl stress than that of the control; soluble sugar content generally appears a changing trend of first increasing and then decreasing, and is higher than that of the control. It is suggested that F. americana has a stronger tolerance to NaCl stress.