Abstract: In order to screen Suaeda salsa growth-promoting bacteria and to assess its effect on alfalfa seed germination and seedling growth under salt stress, robust and pest free suaeda plants and rhizosphere soil were collected, the strains were purified, isolated, identified, sequenced by 16 S rDNA and analyzed for salt and alkali tolerance（NaCl, Na₂SO₄, NaHCO₃ and Na₂CO₃ was 9∶1∶1∶9 with a concentration of 0,50,100,150,200,300 mmol/L）.At the same time, the effects of different strains on germination rate, root length, bud length and fresh weight of alfalfa seeds under salt-alkali stress were studied. The results showed that five strains were isolated from the rhizosphere soil and the plant of Suaeda salsa, which were JT2, JT4, JT8, JG1 and JJ5. JT2, JJ5 and JG1 were identified as Serratia, JT4 as Maltooligomonas maltophilia and JT8 as Bacillus parvus by biochemical identification and 16 S rDNA sequence analysis. The growth of JT2 and JJ5 was inhibited when saline-alkali concentration was higher than 50 mmol/L. The growth of JT4 was inhibited when saline-alkali concentration was ≥100 mmol/L.The JG1 growth was inhibited when the saline-alkali concentration was ≥150 mmol/L.The growth of JT8 was inhibited when the saline-alkali concentration was 50-150 and 300 mmol/L.When the concentration of salt-alkali solution was 50, 100 mmol/L, the germination rate and root length of alfalfa seeds treated by various isolates were significantly higher than those of the control（without suspension, P＜0.05）.When the saline solution concentration was 150 mmol/L, the seed germination rate and root length of ALfalfa treated by JT4 were significantly higher than that of the control（P＜0.05）, the seed germination rate of alfalfa treated by JJ5 and JT8 were significantly higher than that of the control（P＜0.05）, and the root length was slightly higher than that of the control（P＞0.05）.The germination rate and root length of alfalfa treated by JT4 were significantly higher than those treated by JJ5 and JT8（P＜0.05）.When the concentration of saline solution was 100 mmol/L, the seed bud length of alfalfa treated by all isolates was significantly higher than that of the control（P＜0.05）.When the saline solution concentration was 150 mmol/L, the seed bud length of alfalfa treated by JT4 was significantly higher than that of the control（P＜0.05）, and that treated by JJ5 and JT8 was slightly higher than that of the control（P＞0.05）.When the concentration of saline solution was 100 mmol/L, the fresh weight of alfalfa seeds treated with JT4, JJ5, JT2, JG1 and JT8 was significantly higher than that of the control（P＜0.05）.When the saline solution concentration was 150 mmol/L, the fresh weight of alfalfa seeds treated with JT4, JJ5 and JT8 was significantly higher than that of the control（P＜0.05）, and the fresh weight of alfalfa seeds treated with JT4 was significantly higher than that of JJ5 and JT8（P＜0.05）. The results indicated that all the five isolates were Suaeda salsa growth-promoting bacteria, and JT4 had the best effect on alfalfa seed germination and seedling growth under saline-alkali stress.