Abstract: 【Objective】 To study the mechanism of alkali resistance of Agropyron cristatum 'Tawukumu'and the relationship between organic acids secreted by roots and pH value in regulating alkali resistance of the plants. 【Methods】 Two kinds of alkaline salts Na₂CO₃ and NaHCO₃ were mixed at a molar ratio of 9∶1. Alkali stress was simulated by artificial simulation under natural alkaline habitat conditions of 10, 30, 60, 90 and 120 mmol/L. The pH value and organic acid species and content of the seedlings were determined to study their physiological response to stress. 【Results】 Under alkaline stress, the radicle and embryo of Agropyron tawukumensis grew slowly, and the radicle growth rate was only 0.40 times that of the control, which was more significantly inhibited. With the increase of the concentration of treatment solution, the roots of seedlings secreted organic acids mainly malic acid and citric acid, which interacted with each other to resist the damage of high pH to plants kept the pH in the roots between 6.65 and 6.68. Although the organic acids secreted by the roots of Agropyricacrassifera increased significantly in the process of alkali stress, they could not prevent the damage of high pH to the plant seedlings. 【Conclusion】 When the concentration of treatment solution is 60 mmol/L, that is, the pH value is 9.8, the organic acid secretion was the most appropriate concentration to regulate the pH value of Agropyricacrassifera root.