The seeds of Rheum palmatum, R. tanguticum and R. officinale were cultured with double layer filter paper and subjected to a series of NaCl stress concentrations (0, 100, 150, 200, 250 mmol/L), and salicylic acid (SA) solution of a series of concentrations (0, 50, 100, 150, 200, 250 mg/L) were used for seed dressing or soaking to carry out salt stress experiments. We measured seed germination and seedling growth indexes of three kinds of rhubarb to reveal the effects of exogenous salicylic acid on rhubarb seed germination and seedling growth under salt stress. Overall, the results showed that: (1) seed germination rates of three rhubarbs decreased with the increasement of NaCl concentration. The cotyledon, hypocotyl, root and seedlings length were all strongly inhibited with the increasement of NaCl concentration. (2) Under the condition of seed dressing, 200 mg/L SA treatment promoted the seedling growth of R. palmatum under 200 mmol/L NaCl stress; 250 mg/L SA inhibited the germination rate of R. tanguticum seeds under 200 mmol/L NaCl stress; 200 mg/L SA inhibited the germination potential of R. officinale seeds under 100 mmol/L NaCl, 150 mg/L SA inhibited the germination rate of rhubarb seeds under 100 mmol/L NaCl stress, 250 mg/L SA inhibited the seedling growth of rhubarb seedlings under salinity stress. (3) Under seed soaking conditions, 50 mg/L SA increased the germination rate of R. palmatum seeds under 200 mmol/L NaCl stress, and the growth of roots and seedlings was promoted by 250 mg/L SA treatment, and 250 mg/L SA promoted the growth of roots and seedlings of R. palmatum seedlings under 200 mmol/L NaCl concentrations; 200 mg/L SA promoted germination potential of R. tanguticum under 200 mmol/L NaCl stress, and the growth of roots and seedlings was promoted by 50 mg/L SA treatment; 50 mg/L SA promoted root and seedling growth of R. tanguticum under 200 mmol/L NaCl stress; 100 mg/L SA promoted the growth of roots and seedlings of R. officinale under 100 mmol/L NaCl stress. Therefore, it can be concluded that the three kinds of rhubarb seeds had the same response trends to salt stress, but had great differences in response to seed dressing and seed soaking with different concentrations of SA.