Studies on the survival and growth strategies of the dominant species Nitraria tangutorum in desert ecosystem can help serving ecological restoration and soil desertification prevention. The N. tangutorum samples were collected from three plots where differed in relative moisture and drought degree showed as Plot1 < Plot2 < Plot3, to explore the C ∶ N ∶ P stoichiometry and non-structural carbohydrate (NSCs) accumulation and allocation in organs of roots, stems and leaves. Meanwhile, the concentrations of soil organic matter, total nitrogen and phosphorous were analyzed in the same sites. The results showed that: (1) with increasing drought stress, NSCs concentrations decreased, while soluble sugar (SS) concentrations increased first and then decreased, and starch (ST) concentrations decreased first and then increased in N. tangutorum organs of leaves, stems and roots. The total N and P concentrations in leaves significantly increased and then decreased with increasing drought stress, C ∶ N ratios and C ∶ P ratios showed the opposite trend and the N ∶ P ratios in leaves were greater than 16 in Plot3. (2) The SS concentrations in roots were higher, while ST contents in roots were lower, than those in stems and leaves in Plot1 sampling site. In Plot3 sampling site, the SS concentrations were higher in leaves than in stems and roots, while ST concentrations were higher in roots than in leaves and stems. Carbon contents in roots and stems of N. tangutorum were significantly higher than those in leaves. Except for P concentrations in Plot3 sampling site, total N and P contents in leaves were higher than those in stems and roots among all three sampling sites. (3) The N and P concentrations in leaves were positively correlated with SS concentrations but negatively correlated with ST concentrations in stems and leaves respectively, and P concentrations were positively correlated with ST concentrations but negatively correlated with SS concentrations in roots. Based on these results, we speculated that water and phosphorous were the limiting factors for the growth of N. tangutorum under drought stress. N. tangutorum adapted to drought by allocating NSCs among organs, and by increasing nitrogen and phosphorous use efficiency. P played an important role in inter-converting of SS and ST, and regulating NSCs composition.