Abstract: Echinops gmelini is an annual wild plant distributed in arid desert areas of North China. The changes of water content, Na⁺, Cl^-, Si⁴⁺, K⁺, Ca²⁺ contents and the K⁺/Na⁺, Ca²⁺/Na⁺, Si⁴⁺/Na⁺ ratios were measured in E. gmelini seedlings in a water control and under different concentrations (100, 200, 300, 400 mmol/L) of NaCl stress: the water contents were found to increase by 9.86%, 1.41%, 4.23%, and 8.45%, respectively. Therefore the ability to absorb water was enhanced under salt stress, resulting in dilution of the cell’s salt ion concentration to reduce physiological drought caused by salt ions. Na⁺ and Cl^- contents of roots were higher than those of leaves under salt stress, so the salt ion damage on the leaves was reduced; The Si⁴⁺, K⁺, Ca²⁺ concentrations and K⁺/Na⁺, Ca²⁺/Na⁺, Si⁴⁺/Na⁺ ratio in roots under salt stress were significantly reduced compared with no salt stress. Based on the ion selective absorption of Na⁺ and K⁺, E. gmelini roots retained more Na⁺ and reduced the Na⁺ damage to leaves; The K⁺ selective absorption to leaves of E. gmelini were strengthened under NaCl stress, which was significant for maintaining iron homeostasis and photosynthesis in shoots.