In order to discuss the response of plant, litter, and soil nutrient content and stoichiometric ratio to the addition of multiple restrictive nutrients in the soil, clarify the stoichiometric dynamics of the plant-litter-soil continuum and the synergistic effects between components, Ningxia desert grassland was used as the research object to carry out nitrogen (N) and phosphorus (P) addition experiments. The experimental treatment includes four treatments:control (CK), N addition (10 g/m²/a), P addition (10 g/m²/a), and co-addition of N and P (10 g/m²/a N+10 g/m²/a P). The results showed that:(1) The co-addition of N and P significantly increased the N and P content of plant, litter and soil, while significantly reduced plant C:N and C:P ratio as well as C:P and N:P ratio of soil and litter. P addition significantly increased plant, litter, and soil P content, while significantly reduced C:P and N:P ratio of plant, litter, and soil. The N content and N:P ratio of plant and litter were increased by N addition, but no significant change of plant N content was observed from N addition. (2) The content of C, N, P and N:P ratio showed the order as plant> litter> soil, C:N and C:P ratio showed the order as litter> plant. (3) N addition increased plant phosphorus reabsorption efficiency and reduced plant nitrogen utilization efficiency. P addition increased plant nitrogen reabsorption efficiency and reduced plant phosphorus utilization efficiency. The co-addition of N and P improved the plant nitrogen reabsorption efficiency and phosphorus reabsorption efficiency, and reduced plant nitrogen utilization efficiency and phosphorus utilization efficiency. (4) The N, P content and the stoichiometric ratio of plant, litter and soil were significantly correlated. Among them, N, P, N:P ratio of plant were significantly positively correlated with N, P, N:P ratio of litter and soil. Litter P and C:N ratio were significantly negatively correlated with C:P and N:P ratio of plants and soil. (5) The plant and litter N had strong homeostasis (1/H=0.45 and 0.48), and P and N:P ratio of plant and litter had weak homeostasis (1/H=0.80, 0.73 and 0.81, 0.78) to maintain N balance under N limited in soil. The plant growth was limited by N in desert grassland. The N limitation of desert grassland was alleviated by N addition, while was aggravated by P addition and co-addition of N and P. Desert grassland plant could adapt to the change of soil N and P supply mainly by changing the nutrient utilization strategies and reabsorption efficiency.