Abstract: A pot experiment was conducted to study the influence of different concentrations (0, 50, 100, 200 and 400 mmol/L) of NaCl on the growth, the contents of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX), water potential, and on the contents of soluble sugar and proline in the assimilation shoots of Haloxylon ammodendron. The growth of H. ammodendron was promoted at a lower NaCl concentration (50 mmol/L). Compared with the control, plant height and basal stem diameter were significantly inhibited in the 400 mmol/L NaCl treatment, while crown area, dry mass of assimilation shoot and shoot dry mass were considerably reduced under NaCl treatments at concentrations ≥200 mmol/L and root dry mass was considerably reduced under NaCl treatments at concentrations ≥100 mmol/L. Thus, the suppressive effect on root dry mass was greater than on crown area, dry mass of assimilation shoot and shoot dry mass, which were more affected than plant height and basal stem diameter. Root/shoot ratios decreased markedly under NaCl treatments at concentrations ≥100 mmol/L compared with the control. Compared with the control, there were significant accumulations of H₂O₂ and MDA in the assimilation shoot of H. ammodendron at higher NaCl concentrations and the activities of SOD, POD, CAT and APX increased at low NaCl concentrations (≤100 mmol/L), suggesting that together they play an important role in the scavenging of reactive oxygen species. However, the activities of CAT and POD began to reduce at NaCl concentrations ≥200 mmol/L compared with the control, indicating the scavenging efficiency of the antioxidative enzyme system weakened. Water potential reduced with an increase in NaCl concentrations. The contents of soluble sugar and proline initially increased but then decreased compared with the control.