Abstract: In order to investigate the alkaline salt tolerance of seeds and seedlings and the variation of seed germination and seedling growth under alkaline salt stress. In this experiment, the seeds and seedlings of Bretschneidera sinensis were treated with 0.1%−0.5% Na₂CO₃, and their germination, morphology and physiological indexes were determined to observe the tolerance of the seeds and seedlings to alkaline salt. The results showed that the low concentration alkaline solution could promote the seed germination and seedling growth. When the concentration reached 0.1%, the vigor index increased 79% compared with the control group. Seedling height and root length increased 46% and 34% respectively. High concentration of alkaline solution inhibited the seed germination and seedling growth, and all the indexes decreased. When the concentration reached 0.5%, the seedling height and root length were decreased by 50% and 33%, respectively, compared with the control group. With the increase of Na₂CO₃ concentration, soluble sugar, soluble protein and MDA, POD, SOD increased slowly under alkaline stress. Therefore, it shows that B. sinensis has a certain alkalinity resistance.