Abstract:【Objective】To study the effects of drought stress on the distribution and stoichiometry of carbon, nitrogen and phosphorus in different organs of Pinus yunnanensis seedlings.【Methods】The 1-year seedling of Pinus yunnanensis was used as experimental material, and four water treatments were set, that is, the relative water content of soil was controlled at 90%±5%(CK), 75%±5%(mild drought), 60%±5%(moderate drought) and 45%±5%(severe drought), respectively. The contents of C, N and P in leaves, stems, coarse roots and fine roots of Pinus yunnanensis seedlings under drought stress were determined, and the stoichiometric characteristics of carbon (C), nitrogen (N) and phosphorus (P) were analyzed. 【Results]】(1) Compared with the appropriate water treatment, the C content in leaves, stems and fine roots of Pinus yunnanensis seedlings decreased under drought stress, but increased in coarse roots. N content decreased in coarse roots and increased in fine roots. P content increased in leaves and decreased in stems. C:N increased first in coarse roots and then decreased in fine roots. C:P decreased in leaves; N:P decreased in leaves and increased in stems. (2) The order of variability of each element content was P > N > C. The variability of C content in leaves and stems was small and the degree of variation was weak, and the variability in fine roots was the largest; The variability of N content and C:N was the largest in fine roots. The variability of P content was the largest in leaves and the smallest in coarse roots. C:P variability is the largest in the stem, N:P variability is the largest in the stem and the smallest in the coarse root. (3) There was no significant correlation between the contents of C and P in leaves, stems, coarse roots and fine roots; there was a significant negative correlation between the contents of N in leaves and coarse roots, and a significant positive correlation between the contents of N in stems and fine roots. In addition, there was a significant positive correlation between the contents of N and P in stems and coarse roots.【Conclusion】The results showed that the growth of Pinus yunnanensis seedlings was restricted by N element, and the utilization efficiency of N and P increased with the increase of drought stress. The overall variability of C, N and P contents in coarse roots and fine roots of Pinus yunnanensis seedlings was higher than that in leaves and stems, and the root system was more sensitive to soil water environment.