To study the salt-tolerance mechanism of Thermopsis lanceolata,we determined the growth parameters,organic osmotic adjustment substance contents and inorganic ions such as Na⁺,K⁺ and Ca²⁺ cation contents of T.lanceolata test-tube plantlets which have been growing for 30 d under 0,0.2%,0.4%,0.6%,0.8%,1.0% NaCl and Na₂SO₄ Stress.The results showed:(1)With NaCl and Na₂SO₄ concentration increasing,the contents of free proline and soluble sugar in leaves of T.lanceolata test-tube plantlets increased significantly,but the increasing extent of free proline under NaCl stress was greater than that under the same Na₂SO₄ concentration stress,while the increasing extent of soluble sugar content under NaCl stress was smaller than that under the same Na₂SO₄ concentration stress;the soluble protein content increased first then decreased with the increasing of NaCl concentration while went up continuously with the increasing of Na₂SO₄ concentration.(2)Na⁺ content of T.lanceolata test-tube plantlets went up continuously with the increased of the NaCl and Na₂SO₄ concentrations and the Na⁺ contents of all treatments were significantly higher than those in the control.Ca²⁺ and K⁺ content in leaves presented a decreasing trend,which were significantly lower than that of the control,respectively.In roots,K⁺ content first increased and then declined.Compared with NaCl,Na₂SO₄ stress caused a lower increase of Na⁺ content and lower reduction of K⁺ and Ca²⁺ contents in leaves;Na⁺/K⁺and Na⁺/Ca²⁺ ratios increased with the increase of salt content;In leaves,Na⁺/K⁺and Na⁺/Ca²⁺ ratios under NaCl stress were higher than that under Na₂SO₄ stress,while Na⁺/K⁺and Na⁺/Ca²⁺ ratios in roots were lower than that under Na₂SO₄ stress.T.lanceolata test-tube plantlets under salt stress may adapt to salt environment depressing Na⁺ contents,increasing soluble sugar and soluble protein contents in leaves,higher K⁺ and Ca²⁺ contents and decreased Na⁺/K⁺and Na⁺/Ca²⁺ ratios in roots.In words,the adaptation of T.lanceolata to NaCl stress was smaller than that to Na₂SO₄ stress.