Foliar stoichiometry is a window to understand the biogeochemical cycle, as well as understand plant growth and ecological adaptability. Studying the foliar stoichiometry of artificial forests is of great significance for further optimizing ecological projects. In order to reveal the similarities and differences of the main greening species (Sabina chinensis, platycladus orientalis, Picea asperata) to environmental adaptability in the north and south mountains of Lanzhou City, the foliar stoichiometry traits of three trees were compared. The results showed that the foliar C contents of Picea asperata and Sabina chinensis (497.64 g/kg, and 496.02 g/kg, respectively) was significantly higher than that of platycladus orientalis (484.12 g/kg). The foliar N content of platycladus orientalis (17.70 g/kg) was significantly higher than that of Sabina chinensis and Picea asperata (14.04 g/kg,15.62 g/kg, respectively), and this trend was also found for foliar P content, with the former being 1.66 g/kg, and the latter two being 1.42 g/kg and 1.40 g/kg, respectively. The order of variation coefficients of C, N, and P were Sabina chinensis < platycladus orientalis < Picea asperata. The foliar C ∶ N and C ∶ P of Sabina chinensis (35.42 and 360.52, respectively) and Picea asperata (33.32 and 389.57, respectively) were both significantly higher than the C ∶ N (28.17) and C ∶ P (306.07) of platycladus orientalis. The foliar N ∶ P (11.88) of Picea asperata was significantly higher than that of Sabina chinensis (10.20) and platycladus orientalis (10.98). The order of variation coefficients of C ∶ N, C ∶ P, and N ∶ P were Sabina chinensis < platycladus orientalis < Picea asperata. The foliar N contents of platycladus orientalis and Picea asperata were positively related to the foliar P content, but were negatively related to the foliar C ∶ N and C ∶ P. The foliar P contents of the three trees were negatively related to the foliar C ∶ P and N ∶ P, with being positive correlation with each other. The foliar C content of Sabina chinensis was positively related to the foliar N content, yet for platycladus orientalis it was negatively related to the foliar N content, but positively related to the foliar C ∶ N and C ∶ P. The redundant analysis showed that foliar stoichiometry traits were mainly influenced by soil organic carbon (SOC): soil total nitrogen (STN), with the foliar C content of Sabina chinensis being positively correlated with SOC, SOC ∶ STN, and soil pH; the foliar N content of the three trees were all positively correlated with SOC, SOC ∶ STN, and SOC ∶ STP. The foliar N content of Picea asperata, and the foliar P content of platycladus orientalis and Picea asperata were negatively correlated with soil total phosphorus (STP), while the STP was positively correlated with the foliar C ∶ P and N ∶ P of platycladus orientalis and foliar C ∶ N of Picea asperata, respectively. The foliar C ∶ N values of the three trees were negatively correlated with SOC ∶ STN and SOC ∶ STP. The results suggest that three major trees have different adaptation strategies under poor nutrient habitat, with a defensive strategy for Sabina chinensis and Picea asperata, and a competitive strategy for platycladus orientalis. Though Picea asperata may be the most suitable species that were planted in north and south mountains of Lanzhou City, the growth of the three trees were all limited by STN.