With Leymus chinensis seedlings as the research object, we set 0, 10 and 20 times Fe²⁺ (Zn²⁺) concentration by adjusting the contents of iron and zinc in total nutrition medium (CK: 0.05 mmol/L Fe²⁺, 0.015 mmol/L Zn²⁺) as Fe₀ (Zn₀), Fe₁₀ (Zn₁₀), Fe₂₀ (Zn₂₀). And adding 0.15 mmol/L Zn²⁺ alone or 10 mmol/L Ca²⁺, 5 mmol/L Mg²⁺, 20 mmol/L K⁺ to the high concentration iron medium at the same time. We measured the growth index and mineral element contents of seedlings after 6 days of culture, as well as the antioxidant indexes and related gene expression in the roots of seedlings treated with high concentration iron (Fe₂₀), to explore the effects of different concentrations of Fe²⁺ and Zn²⁺ on the growth, mineral element absorption and accumulation, antioxidant indexes and gene expression in Leymus chinensis seedlings. The results show that: (1) deficiency of Zn (Zn₀) significantly inhibited the increase of fresh weight and the accumulation of Zn elements, but promoted the accumulation of Fe and Mg elements. High concentration of Zn (Zn¹⁰, Zn²⁰) significantly promoted the growth of seedling leaves and the accumulation of Zn. Deficiency of Fe(Fe₀) significantly inhibited the root length, fresh weight and the accumulation of Fe elements, and promoted the accumulation of Mg and Zn elements in seedlings. High concentration of Fe(Fe₁₀, Fe₂₀) significantly inhibited the root and leaf growth, root hair development and the accumulation of Ca, Zn, Mg and K elements in L. chinensis seedlings. (2) Increasing the concentration of Zn²⁺ and Ca²⁺, Mg²⁺, K⁺ could not restore the inhibitory effect of high concentration iron stress on seedling growth. (3) After treatment of L. chinensis seedlings with high concentration of iron (Fe₂₀) for 48 hours, the activities of peroxidase, superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and the contents of malondialdehyde, ascorbic acid and reduced glutathione in roots increased significantly, while the gene expressions of nicotianamine synthase and peroxidase were downregulated significantly and plant germininlike protein were upregulated significantly. The research found that the growth and development of L. chinensis seedlings and the accumulation of mineral elements were not sensitive to the change of Zn²⁺ concentration in the environment, but were significantly inhibited by the high concentration of Fe²⁺ in the environment, and caused serious oxidative stress damage, which this damage cannot be recovered under the conditions of adding Zn²⁺ or adding Ca²⁺, Mg²⁺, K⁺ at the same time.