Abstract: 【Objective】 To discuss the adaptation of S.tianschanica Rupr. to light intensity by analyzing the leaf stomata characteristics and photosynthetic physiological changes of Sorbus tianschanica Rupr. seedlings under different light intensity, in the hope of providing reference for the conservation and domestication of S.tianschanica Rupr. seedlings. 【Methods】 Two year seedlings of S.tianschanica Rupr. were used as materials, and four light gradients (L₁:50%, L₂:30%, L₃:10% and CK: 100%) were set up by sunshade nets with different number of needles to conduct pot experiments, and the changes of stomata characteristics, photosynthetic fluorescence parameters and chlorophyll content of S.tianschanica Rupr. seedlings under different light intensities were analyzed. 【Results】 The seedlings of S.tianschanica Rupr. had the best growth under L₂ treatment, and their seedling height and ground diameter were the largest. The results showed that with the decrease of light intensity, the stomatal density of S.tianschanica Rupr. leaves gradually increased and there were significant differences among different treatments (P < 0.05), but the changes of leaf stomatal length, width, perimeter, area and opening under different light conditions were not significant (P > 0.05). The Pn, Gs and Tr of S.tianschanica Rupr. seedlings increased first and then decreased with the decrease of light intensity, and Ci increased gradually. Under L₂ treatment, the Pn of the leaves was the highest, 17.07 μmol/(m²·s). The Fv/Fm of the leaves increased with the decrease of light intensity, and the Fv/Fm of the leaves under all treatments was significantly higher than that under CK treatment (P < 0.05). The ETR of leaves reached the highest level in L₂ treatment, and there were significant differences in ETR of leaves between treatments (P < 0.05). The diameter of ФPSⅡ of the leaves was L₁ > L₂ > CK > L₃. The contents of Chl a, Chl b, Chl t and Car increased with the decrease of light intensity, and Chl a/b decreased with the decrease of light intensity. Light intensity was positively correlated with Pn and Tr (P < 0.01), and Fv/Fm was positively correlated with ETR, Chl a, Chl b and Chl t contents (P < 0.01). 【Conclusion】 The results show that the light intensity of L₂ treatment (light intensity of 30%) has more potential to promote photosynthesis and growth of S.tianschanica Rupr. seedlings. moderate shading should be carried out to improve the quality of seedlings and introduce and cultivate them.