Plant nutrient stoichiometry can be used to distinguish the biological entities based on element composition and responses to environmental factors. We determined the N and P stoichiometry for leaves, litter, and soil associated with 3 dominant tree species:Robinia pseucdoacacia, Quercus liaotungensis, and Pinus tabulaeformis, at 39 sites in 29 county-level cites of the Shaanxi Province. We aimed to distinguish the differences in leaf, litter, and soil N and P stoichiometry among the different tree species, and their relationships with environmental factors in the Shaanxi Province. Leaf N and P concentrations and their ratios, were Robinia pseucdoacacia > Quercus liaotungensis > Pinus tabulaeformis. Compared with plant leaves, the range and quantity of litter N and P concentration significantly reduced (P < 0.05), and the order was still Robinia pseucdoacacia > Quercus liaotungensis > Pinus tabulaeformis, while the order for the N:P ratio was Pinus tabulaeformis > Quercus liaotungensis > Robinia pseucdoacacia. There were no significant correlations (P < 0.05) between Robinia pseucdoacacia, Quercus liaotungensis, and Pinus tabulaeformis leaf N (or P) and soil N (or P), indicating that their growth was not limited by N or P. In total, there were significant correlations between leaf P and soil P (P < 0.05), which indicated that the growth of the plant was limited by P in the Shaanxi Province. Leaf N and P increased with mean annual temperature and precipitation, especially for Robinia pseucdoacacia. The leaf N:P ratio for the 3 tree species did not clearly correlate with the environmental factors. Litter N increased with mean annual temperature and precipitation, and decreased depending on the latitude and longitude. Although litter P showed no significant relationships with temperature and latitude (P < 0.05), it declined with precipitation and longitude. Litter N:P ratio increased with temperature and precipitation and decreased with latitude. Soil N and P increased with latitude and altitude, and decreased with mean annual temperature, mean annual precipitation, and longitude. The soil N:P ratios demonstrated an opposite trend. Soil P was more closely correlated with environmental factors than N, and the relationship between the 0-10 cm and 10-20 cm N and P stoichiometry in terms of environmental factors was almost the same.