Soil elemental stoichiometry can characterize soil nutrient storage, supply capacity, and limitation. C:N:P stoichiometry is considered an important indicator of soil nutrient status during soil development. Drylands are critical terrestrial environments and are considered to be the largest biome on Earth. Our study aimed to investigate the C:N:P stoichiometric characteristics and drivers of surface soil in the drylands of China. Our study was conducted based on soil nutrient data derived from the National Tibetan Plateau Data Center and environmental data. We used structural equation modeling, variation partitioning analysis, redundancy analysis, and other methods to investigate whether there are spatial patterns and interrelationships among soil C, N, P, and C:N:P in the drylands of China and to analyze the drivers influencing the changes in C, N, P, and C:N:P. Similarly, C, N, and P density of the surface soil in the drylands of China were low (3.44, 0.14 and 0.10 kg/m2, respectively). Highly significant non-linear relationships were observed between all the nutrients and their corresponding stoichiometric ratios, except for C and P, which exhibited significant linear relationships. Aridity and plant (vegetation) were the main drivers of soil C and N density in drylands, while the main driver of P density was aridity; the soil environment contributed most to the relative changes in C, N, P, and C:N:P. In conclusion, the soil C, N, and P densities in the drylands of China were low. Plant, climate, and soil together explained 47.5–81.3% of the total variation in C, N, P, and C:N:P. Our results indicated that the soil surface nutrient density is low in drylands; changes in C, N, P, and C:N:P are not influenced by a single factor but are driven by a combination of environmental factors. The results of this research provide a specific reference for a comprehensive understanding of changes in soil nutrient densities in drylands under global environmental change. For example, when plowing dryland farmland, the stability of the soil can be protected against land erosion and degradation by increasing soil organic matter; additionally, when applying fertilizers to dryland farmland, the amount of N fertilizer can increase, and the amount of P fertilizer can decrease in the future.
