Abstract: The effect of salicylic acid of different concentrations (SA, 0.1, 0.2, 0.3, 0.4 mmol/L) on soybean (Glycine max L.) seed germination and seedling physiology under 100 mmol/L NaCl stress were investigated by means of sand culture. The results showed that the seed germination, root and stem growth, biomass and osmotic adjustment were prompted, while the membrane permeability was decreased by high concentration of salicylic acid under 100 mmol/L NaCl stress. But overly high concentration of salicylic acid inhibited the growth and aggravated the membrane permeability. And 0.2 mmol/L SA has significant effects on seed germination, and at 0.3 mmol/L the effect of SA is most obvious on seedling physiology under NaCl stress.