In order to study the distribution characteristics of the fine roots of Populus simonii with different degradation degrees in Bashang area, this paper used soil column method to compare the distribution rules and difference of fine root parameters in horizontal and vertical directions in P. simonii stands with different degradation degrees (no degradation, moderate degradation and severe degradation), and analyzed the proportion of root parameters in different soil layers. The results showed that:(1) With the decreasing of soil moisture content, the degradation degree of P. simonii increased, the proportion of fine roots in the surface layer increased, and its proportion in the deep layer decreased. (2) In the vertical direction, the fine root biomass of P. simonii in 0-20 cm soil layer was significantly higher than that in other soil layers (P < 0.05), and the root length density, root surface area density and root volume density decreased significantly with the deepening of soil layer. In 0-20, 20-40, 40-60, 60-80 and 80-100 cm soil layers, the root surface area density and root volume density of fine roots followed the order of no degradation>moderately degradation>severely degradation. (3) In the horizontal direction away from the trunk, the root length density of fine roots increased at first and then decreased in no degeneration and moderately degeneration stands, while there was no significant difference among 0-50, 50-100 and 100-150 cm soil layers in severely degenerated P. simonii stand, and that increased significantly in 150-200 cm soli layer and reached the maximum (0.465 7 cm/cm³) (P < 0.05). The root surface area density and root volume density of fine roots all followed the order of no degradation>moderately degradation>severely degradation at four horizontal distances. The fine root biomasses of no degraded P. simonii were all the largest (19.53, 15.74, 14.17 and 14.20 g). The root volume density decreased with the increasing of horizontal distance. The results of this study could provide a scientific reference for exploring the fine root distribution pattern and degradation reasons of shelterbelts, and for guiding the vegetation restoration and reconstruction in Bashang plateau.