Abstract: In order to promote the breeding of salt alkali tolerant soybean varieties and the rational development and utilization of saline alkali land,four soybean varieties from Heilongjiang Province（Hongyan 12,Kenkedou 14,Kenkedou 28,Kendou 62）were used as test materials.Six gradients(0,30,60,90,120and 150mmol·L^-1)of salt alkali mixed solution(NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃ molar ratio of 1∶9∶9∶1)were used to treat the test materials with salt alkali stress.The germination experiment was conducted using filter paper culture in a culture dish to analyze the effects of salt alkali stress on soybean seed germination parameters and embryonic root parameters.The results showed that low concentration saline alkali stress(30 mmol·L^-1)treatment had a certain promoting effect on the germination of Hongyan 12,but had a relatively small inhibitory effect on the germination rate and germination potential of other varieties.As the concentration of saline alkali mixture increases,the inhibitory effect on germination potential and germination rate of the treatment also gradually increases.The same concentration of saline alkali mixture has different effects on germination potential and germination rate of different varieties;When the concentration of salt alkali stress was≥60mmol·L^-1,the germination rate,germination potential,and salt alkali tolerance index of soybean seeds decrease;When the concentration of salt alkali stress was 90mmol·L^-1,compared with CK,the differences in germination potential,germination rate,and salt alkali tolerance index all reach significant levels.When the concentration of salt alkali stress was 150mmol·L^-1,the germination index was most inhibited and the embryonic root growth was inhibited.As the concentration of salt alkali mixture increases,the inhibitory effect on root length,root fresh weight,and dry weight became stronger.Different varieties were subject to different degrees of inhibition.Compared with germination potential and germination rate,embryonic root length,embryonic root fresh weight,and dry weight were more inhibited and decrease more with the increase of salt alkali stress.Under the same treatment concentration,the inhibition of embryonic root dry weight varies among different soybean varieties.When the concentration of saline alkali mixture was 90mmol·L^-1,the differences in embryonic root parameter indicators and CK between each treatment reach a significant level.Based on the above results,a salt alkali stress concentration of 90mmol·L^-1 could be used as the appropriate concentration for identifying salt alkali tolerance in soybean germination.