The study was conducted to indicate ecological stoichiometry and homeostasis characteristics among different organs of typical shrub communities in Luo Mountain, Ningxia, and to reveal plant nutrient utilization strategies and growth-limiting elements in this region. Leaves, branches, roots, and soil were collected from four shrub communities: Spiraea mongolica, Ostryopsis davidiana, Cotoneaster soongoricus, and Caragana korshinskii communities in Luo Mountain, Ningxia. This study systematically analyzed the differences and correlations of C, N, and P stoichiometric characteristics among plant organs of these four shrub communities, as well as homeostasis characteristics, and quantified the independent contributions of soil factors on the stoichiometry of each organ based on hierarchical partitioning. The results showed that the contents of C and C/N ratios in leaves, branches, and roots of the Caragana korshinskii community were significantly lower than those of the other shrub communities, whereas the N contents in leaves and branches, as well as the P content in branches, were significantly higher than those of the other shrub communities. Leaf C/P of the Cotoneaster soongoricus community was significantly higher than other shrub communities. Across all communities, leaf and branch C contents were significantly higher than roots, and N contents followed the trend: leaf>branch>root. In addition, C content was negatively correlated with N and P contents, and N content was positively correlated with P content in all organs. N, P, C/N, and C/P were positively correlated among leaves, branches, and roots. Leaf N/P was greater than 16 in all shrub communities, indicating P-limited growth, and P exhibited strong homeostasis. The homeostasis of leaves was stronger than branches and roots, which reflected preferential nutrient allocation to leaves in all shrub communities. Soil C exerted the greatest independent influence on the ecological stoichiometry of all organs. These findings provide a scientific basis for vegetation conservation and restoration in mountain ecosystems of desert-steppe transition zones.