Abstract: This study characterized variation in leaf phenotypic diversity across an elevational gradient in natural populations of Sophora moorcroftiana (Benth.) Baker, examined associations between leaf phenotype and geographic and climatic variables, and provided a scientific basis for the collection, preservation, and utilization of high-quality germplasm resources. Natural populations from two urban areas of the Xizang Autonomous Region were investigated. Eight leaf phenotypic traits were measured in four natural populations of S. moorcroftiana distributed across different elevations and analyzed using nested analysis of variance, correlation analysis, Mantel test, and principal component analysis. Results showed substantial phenotypic variation among populations. Except for leaflet number, all leaf traits differed significantly among populations (P<0.01). Along the elevation gradient, leaf phenotypic diversity showed a decreasing trend, with an average coefficient of variation (CV) of 18.214%. Based on correlation analysis, leaf length, leaf width, leaf shape index, leaf dry weight, and specific leaf weight were significantly negatively correlated with longitude, average annual temperature, and average temperature in January and July (P<0.01), but significantly positively correlated with average annual precipitation (P<0.01). Overall, leaf phenotypic diversity in S. moorcroftiana declined with increasing elevation, and the degree of variation was strongly associated with geographic and climatic factors. Most variation in leaf phenotypic traits was attributable to differences among populations.