Abstract: In this paper,analysis was made of the biomass allocation,carbon,nitrogen and phosphorus content in fine roots of Hippophae rhamnoides under nitrogen deposition in Western Sichuan Plateau.The results showed that:(1) nitrogen deposition had a significant promotion effect on the total biomass of fine roots,mainly displaying that of the coarser roots; (2) there was no significant change in the total nitrogen content of fine roots under nitrogen deposition,and the total phosphorus content decreased significantly,which made the total C/P and N/P significantly increase; (3) the results of chemical measurement showed that the nitrogen content was relatively lower,whereas the phosphorus content was relatively higher,thus the growth of fine roots might be limited by nitrogen.