[Objective] To investigate the adaptation and tolerance mechanism of Zizyphus jujube seedlings to salt stress in order to provide academic reference for selection of cultivars on saline-alkali land.[Methods] Annual Zizyphus jujube seedlings was taken as research object, pot water control experiments were conducted, to study the influences of different NaCl concentration (CK, 1.5, 3, 4.5, 6, 7.5 g/L) treatment on Z. jujube seedling growth, chlorophyll content, gas exchange parameters and antioxidant enzyme activity.[Results] ① When NaCl concentration was between 0~3 g/L, there was no obvious impacts on the survival rate and growth status of Z. jujube. When the concentration of NaCl was greater than 3 g/L, the survival rate of Z. jujube dropped significantly. Especially, when NaCl concentration was 6~7.5 g/L, the growth of Z. jujube was inhibited seriously. As a result, salt tolerance of Z. jujube was 3 g/L. ② With the increase of salt concentration and stress time, superoxide dismutase(SOD) activity, peroxidase(POD) activity, catalase(CAT) activity of Z. jujube seedling leaf showed a rising trend initially and then decreased. In contrast, the content of malondialdehyde(MDA) and proline(Pro) increased. ③ Photosynthetic pigments content showed a decline trend, similarly, net photosynthetic rate (P_n), stomatal conductance (G_s) and transpiration rate (T_r) showed a decline trend as well. While intercellular CO₂ concentration (C_i) showed a rising trend initially and then decreased. The decline of P_n was caused by stomatal factors at the beginning, and then caused by non-stoma limitation factors.[Conclusion] Low NaCl concentration (<3 g/L) stress has little influence on the survival rate and growth status of Zizyphus jujube. But with the increase of NaCl concentration, the chlorophyll content, antioxidant enzyme system of Z. jujube seedlings will be suppressed, plant growth and development will be severely affected.