Abstract: The effects of Fe²⁺ in acid soil on seeding growth and physiological index of M. sativa were studied in sand culture. M. sativa grew very well at Fe²⁺ concentrations of 10－100 mg/kg. The morphological items measured were rate of germination, plant height, leaf area, number of leaves per plant, and weight of shoots and roots. no less than the control group (pH 6,Fe²⁺ 10 mg/kg); Seedling growth was stimulated, and the physiological index of plants was higher, or significantly (P<0.05) higher than that of other treatments when the concentration of Fe²⁺ was less than 50 mg/kg. Concentrations of Fe²⁺ in the range 100－200 mg/kg soil resulted in a seriously restricted growth of M. sativa and there was a significant (P<0.05) decrease in the measured morphological items. There were significant (P<0.05) differences in electrolyte leakage, MDA content, root activity, soluble sugar content, Fv/Fo and Fv/Fm with different concentrations of Fe²⁺; When the concentration of Fe²⁺ was less than 100 mg/kg, the root activity, electrolyte leakage, Fv/Fo and Fv/F were significantly (P<0.05) higher than those in Fe²⁺ concentrations of 100－250 mg/kg. Chlorophyll content was not correlated with Fe²⁺ concentration.