Abstract: 【Objective】 To investigate the effects of different concentrations of S-nitrosoglutathione (GSNO) on the growth of tomato seedlings under salt stress in the hope of screening out the appropriate concentration to improve the salt tolerance of tomato. 【Methods】 The tomato variety Zhongshu 4 was used as the experimental material and nutrient solution cultivation method was used. Under the stress of NaCl (100 mmol/L), the leaves of tomato seedlings were sprayed with different concentrations of GSNO (0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 mmol/L). The effects of exogenous GSNO on the growth, root activity, chlorophyll content, malondialdehyde (MDA) content, electrolyte permeability and proline content of tomato seedlings under salt stress were determined. 【Results】 (1) NaCl stress significantly reduced plant height, stem diameter, dry weight, fresh weight, root activity, chlorophyll a, chlorophyll b and total chlorophyll content of tomato seedlings; significantly increased MDA content and proline content of tomato seedlings; had no significant effect on electrolyte permeability; (2) exogenous application of 0.1-0.3 mmol/L GSNO can effectively alleviate the inhibition of salt stress on Tomato Seedling Growth and improve salt adaptability by increasing chlorophyll content, root activity and proline content, reducing membrane lipid peroxidation and membrane integrity damage Although the application of GSNO did harm to the growth of Tomato Seedlings under salt stress, it did not inhibit the growth of Tomato Seedlings under salt stress. 【Conclusion】 NaCl stress significantly affected the normal growth of tomato seedlings, and exogenous GSNO with appropriate concentration could effectively alleviate the effect of salt stress on tomato seedlings. In this experiment, 0.1 mmol/L GSNO was the best.