Abstract: In order to explaining adaptability of root systems of Populus simonii Carr.,we had chosen the Populus simonii Carr.artificial plantation in highland in northeast of Mu Us Sandland to study distribution patterns of it's root systems using root auger.The results indicate that: root systems of Populus simonii Carr.has mostly distributed in the depth of 0-40 cm soil,and reached peak value in the surface layer of 0-20 cm depth.The vertical distribution patterns of fine root(D<3 mm) in different slope position and different distance to trunk are similar,and the difference of vertical distribution patterns of thick root(D>3 mm) is conspicuous,but it's density on top of slope is greater than bottom of slope in 1.0 m and 1.5 m distance to trunk.The density of fine root and thick root in bottom of slope are decrease to follow to increase in distance to trunk,however,the density of fine root in top of slope is similar with the former,and that of thick root reached peak value in 1.0 m distance to trunk.The fine root proportion is greater than thick root in the deep soil layer of any distance to trunk,but the thick root proportion in the deep soil layer on top of slope is greater than bottom of slope.It is showed that root systems of Populus simonii Carr.had favorable adaptability for different slope position.