In order to explore the response of growth and hydraulic structure of Jatropha curcas L. to NaCl stress under two nitrogen fertilizer concentrations, three soil salt stress levels ( NaCl content: S1:2 g/kg, S2:4 g/kg, and S3:6 g/kg), two nitrogen fertilizer levels (N1:260 kg/hm2，N2:20 kg/hm2) and a control group (CK， without salt and nitrogen) were tested in the greenhouse. The results showed that Jatropha curcas L. had a certain tolerance to soil salt stress, but its growth was inhibited by different levels of salt stress. The basal stem cross-sectional area, total leaf area, dry matter quality, hydraulic conductivity and water use efficiency of the samples under salt stress were all significantly lower than those of the CK, and the total dry matter mass under all treatments decreased by 9.99%-72.85% compared with the CK. However, higher amount of nitrogen fertilizer can alleviate the damage of low-concentration salt stress on plants. Compared with N1, the basal stem cross-sectional area, total leaf area, and total dry matter mass increased by 20.91%, 24.56%, and 24.35% at the N2 level (P<0.05), respectively. Moreover, the Huber value and the root-shoot ratio increased with the increase of the soil salt stress, and the growth inhibition of the canopy was greater than that of the root system. The specific conductivity significantly decreased with the increase of the soil salt stress, and the growth was hindered. Therefore, it can be seen that when the level of soil salt content is 2 g/kg-4 g/kg, increasing nitrogen fertilizer can effectively improve the biomass accumulation, hydraulic conductivity and water use efficiency of Jatropha curcas L., and it can be used to restore the salt soil.