<p>Under the influence of global climate change, the frequency of intense solar radiation and extreme high temperatures in high-altitude arid regions has heightened environmental stress on the growth of <i>Sophora davidi</i>i seedlings. This study aimed to examine the effects of different shading levels on the growth and photosynthetic performance of one-year <i>S. davidii</i> seedlings. A field experiment was conducted in typical dry-hot valley regions of China, using four shading treatments: CK (full sunlight), S1 (30% shading), S2 (55% shading), and S3 (85% shading). Results showed that the S1 treatment exhibited the highest values in seedling height, biomass, and root-shoot ratio. Furthermore, the net photosynthetic rate (P_n), transpiration rate (T_r), and stomatal conductance (G_s) were also enhanced. As the shading level increased, basal diameter, chlorophyll <i>a</i>/<i>b</i> ratio, and carotenoids content decreased, while leaf area, chlorophyll <i>a</i>, chlorophyll <i>b</i>, and total chlorophyll contents increased. Conversely, under the S3 treatment, seedling height, biomass, P_n, T_r, G_s, and chlorophyll fluorescence parameters (i.e., the maximum quantum yield of PSII, the quantum yield of PSII, the proportion of open PSII) were significantly reduced. Thereby, under full sunlight the reduction in photosynthesis was attributable mainly to stomatal limitation rather than severe photoinhibition, whereas excessive shading (85%) impaired the photosynthetic apparatus (PSII) and inhibited seedling growth. Therefore, a 30% shading treatment was found to be most conducive to seedling development. Appropriate shading measures can effectively alleviate adverse effects from intense solar radiation on <i>S. davidii</i> seedlings, providing a scientific basis for optimizing their cultivation and management strategies in slope ecosystems within high-altitude arid regions.</p>