Abstract: Objective To reveal the nutrient cycling characteristics and dynamic allocation patterns of the plant-soil system during the succession of nebkhas in arid desert regions. Methods Taking Nitraria tangutorum nebkhas at four succession stages (rudimental, developing, stable, and degraded) in the Ulan Buh Desert-oasis ecotone as research objects, leaves, stems, roots and soils at different soil layers were collected to determine C, N, P concentrations and calculate ecological stoichiometric ratios. One-way ANOVA and correlation analysis were used to explore differences among succession stages and nutrient relationships between plants and soil. Results Leaf C peaked at the stable stage (325.20 g/kg), while leaf P decreased continuously with succession, declining by 39.66% at the degraded stage compared with the rudimental stage. Stem N and P were the lowest at the rudimental stage (20.61 g/kg and 0.93 g/kg, respectively). Root nutrient concentrations generally increased first and then decreased, peaking at the developing or stable stage. Soil C, N, and P increased significantly at the stable stage, with a higher increase in deep soil than in topsoil. Nutrient allocation in the system showed distinct organ differentiation: N and P were enriched in leaves (leaf > stem > root > soil), and C was preferentially allocated to stems. Leaf N:P ratios exceeded 16 at all stages and increased continuously with succession. Correlation analysis indicated the strongest coupling between roots and soil. Conclusions Ecological stoichiometric characteristics of N. tangutorum and soil, as well as their interrelationships, varied significantly among succession stages. Nutrient allocation was functionally driven, with remarkable nutrient accumulation in deep soil. The whole succession process was consistently limited by phosphorus, and the limitation intensified with succession. These results provide a theoretical basis for the conservation and restoration of nebkha ecosystems in arid desert regions.