Adjustment of hydraulic architecture and dynamic in non-structural carbohydrates are crucial for understanding the survival prospects and mortality risks of plants under drought stress. We used Populus bolleana Lauche. as the target species. By analyzing the changes of leaf hydraulic traits, photosynthetic physiological characteristics, non-structural carbohydrate (NSC) contents and their components under different water treatments with contrasting, crown heights, we explored the differences in physiological responses and adaptations of leaves at different height levels. The research showed that: (1) during June to August, for the drought treatment group, the leaf water potential, leaf water content and branch water content in the upper part of tree crown were generally lower than those in the lower part; the osmotic potential at full turgor and the water potential at turgor loss point were not significant differences among different crown heights; (2) under drought stress, the net photosynthetic rate decreased with the increase of crown height, the chlorophyll SPAD value was significantly lower in the upper part of the crown than in the lower part, while the water use efficiency was higher in the upper part of the crown than in the lower part; (3) the specific leaf area under drought treatment was significantly lower than that of the control at each crown height, while the Huber value in the middle and upper part was higher than that of the control, but the difference was not significant; (4) the starch content of leaves in upper crown was significantly higher than that in lower crown under drought treatment; the soluble sugar and NSC contents in the upper part of the tree crown were significantly higher than those in the lower part of the tree crown; the contents of soluble sugar, starch and NSC in phloem had no significant difference among different crown heights; the contents of soluble sugar, starch and NSC in fine roots had no significant difference among different water treatments. It was found that the increase in crown height under drought treatment exacerbated drought stress in P. bolleana branches and leaves, resulting in a greater risk of xylem embolism in the upper branches of the crown than in the lower, and led to differences in the distribution and components of NSC among different organs, while P. bolleana plants could mitigate drought stress through adjustments in water use efficiency and morphological adaptations.